Reprinted from the November 2006 edition of the Mössbauer Spectroscopy Newsletter, published as part of Volume 29, Issue 9 of the Mössbauer Effect Reference and Data Journal

This issue of the Newsletter features reports from 14 active Mössbauer research laboratories operating on the Iberian Peninsula. The reports appear in descending order of most active Iberian institutions based on the records of the Mössbauer Effect Data Center.

Universidad del País Vasco / Euskal Herriko Unibertsitatea / University of the Basque Country (UPV/EHU)
Grupo de Caracterización Microestructural, Magnética y Espectroscópica de Materiales con Alto Interés Tecnológico
Bilbao, Spain

Names and Titles of Researchers Professor Fernando Plazaola – Director Dr. José Javier S. Garitaonandia – Magnetic Materials Group Leader Professor José Angel García – Semiconductors Group Leader Dr. Estibaliz Apiñaniz – Scientist Lic. Damian Martín Rodríguez – Ph.D. Student Lic. Asier Zubiaga – Ph.D. Student Lic. Estibaliz Legarra – Ph.D. Student Lic. Eider Goikolea – Ph.D. Student

From left: Asier Zubiaga, J. J. S. Garitaonandia, Eider Goikolea, Fernando Plazaola, Estibaliz Legarra, Damian Martín Rodriguez

History and Areas of Research

The research group at the UPV/EHU is a mixture of two main lines of interest associated with two nuclear spectroscopic techniques: Mössbauer spectroscopy and positron annihilation spectroscopy. At the end of the 1980s, Dr. Fernando Plazaola came to the University of the Basque Country (UPV/EHU) from the Helsinki University of Technology, where he was awarded a Ph.D. based in positron annihilation spectroscopy. At the Science Faculty of the UPV/EHU, he met Dr. Jose Manuel Barandiarán, who had recently formed a group on magnetic materials, and they decided to mix their expertise (magnetism/nuclear systems). The result was the first Mössbauer equipment at the UPV/EHU, a single unit from Halder Electronics located in a very tiny lab. During the first decade, the main area of research was soft magnetic metallic glasses. In this period, Dr. Maria Luisa Fernandez-Gubieda and Dr. Iñaki Orue defended their Ph.D. theses, which had strong Mössbauer orientations. Also during this period the group began collaboration with Dr. Leopold Fournes (MC-CNRS, Bordeaux).

In the mid-1990s, the Mössbauer equipment started to open to other magnetic materials via the Ph.D. thesis of Dr. J. J. S. Garitaonandia, such as nanocrystalline materials produced after crystallization of the amorphous phase, which became very popular due to their excellent soft magnetic properties, and/or problems, such as spin reorientation studies. During those days collaborations with Professor J. M. Greneche (University of Le Mans) and Professor I. Bibicu (National Institute of Materials Physics, Bucharest) began. Indeed, in collaboration with Professor Bibicu, the group built a room temperature CEMS system. Also at that time, within the tiny Mössbauer laboratory, a positron annihilation Doppler broadening spectrometer was built, and the group began collaborating with Professor Alberto Somoza (IFIMAT, Tandil, Argentina).

At the beginning of the 2000s, the group’s research interest moved to intermetallic compounds, in particular to iron aluminides, and the first Ph.D. thesis defended in this field was that of Dr. Estibaliz Apiñaniz (a second thesis will be defended very soon). From these days comes collaboration with Dr. David Schmool (Oporto University, Portugal). At that time the current research group was formed, joining together with Dr. José Angel García, with an interest in positron annihilation spectroscopy for studying semiconductors.

Three years ago, the group moved to a new, much larger laboratory, and has built in it a new Mössbauer chain with a Displex cooling system and a positron annihilation lifetime spectrometer. Two years ago, thanks to the visit of Dr. Garitaonandia to Monash University in Australia, the group began collaboration with Dr. John Cashion, and thanks to this collaboration they have used a Mössbauer isotope (¹⁹⁷Au) different than the usual ⁵⁷Co.

The group studies non-magnetic systems as well, but their main concerns are the following fields:

• FeAl based intermetallics

• Magnetic nanoparticles and their applications (particularly, biomedical applications)

• Large band gap semiconductors for UV optoelectronic and spintronic

Institut de Ciència de Materials de Barcelona (ICMAB)
Department of Crystallography and Solid State Chemistry
Consejo Superior de Investigaciones Científicas
Bellaterra, Spain

Names and Titles of Researchers Dr. Elies Molins – Research Professor Dr. Anna Roig – Tenured Scientist Dr. Lluis Casas – Scientist (now at Universitat Autònoma de Barcelona) Dr. Marti Gich – Post-Doctoral Student Dr. Elisenda Rodríguez – Post-Doctoral Student Ms. Elena Taboada – Ph.D. Student

History and Areas of Research

The Mössbauer laboratory was organized in 1992 thanks to a grant of Generalitat de Catalunya to the ICMAB on the occasion of its new building, located on the campus of the Universitat Autònoma de Barcelona. This laboratory continues the labor initiated by Professor Javier Tejada in the University of Barcelona.

The main research topic in Mössbauer spectroscopy (MS) has been the study of iron-containing nanoparticles of very different compositions and preparation methods (vaporization-condensation, sol-gel, ball milling, natural soils, etc.). The group has also analyzed organometallic compounds (mixed valence, single molecular magnets, ferrocene complexes), ferrofluids, spin transition complexes, and even meteorites. Recently, they have characterized pure samples of ε-Fe₂O₃ and observed spin tunneling effects in Fe₈. The preparation of aerogel-supported nanoparticles by co-synthesis and impregnation methods has afforded interesting materials, such as catalysts active in organic synthesis or transparent magnetic materials exhibiting Faraday rotation effects, which have been characterized by MS.

The laboratory has two spectrometers, one with an Oxford bath cryostat (2 < T < 300 K) and a microMössbauer (with a piezo transducer and a solid state detector, 100 < T < 300 K) which can be used to study very small samples.

The group has published about 40 research papers containing Mössbauer data within the past 10 years, and keeps active collaborations with:

• University of Barcelona, Spain: Dr. C. López, A. Caubet, J. Tejada, V. de la Peña, and G. Aromí

• Universitat Autònoma de Barcelona, Spain: Dr. J. Nogués and A. Vallribera

• ICMM-CSIC, Madrid, Spain: Dr. C. J. Serna and S. Veintemillas

Outside Spain, the group collaborates with:

• Pontifical University of Chile: Drs. J. M. Manriquez and I. Chávez

• Polish Academy of Sciences, Warsaw, Poland: Dr. A. Slawska

• University of La Plata, Argentina: Dr. M. B. Fernández

• University of Le Mans, France: Dr. J. M. Grenèche

• Instituto Balseiro, Centro Atómico Bariloche, Argentina: Dr. R. Zysler

• Russian Academy of Sciences: Dr. E. Shafranovsky

• Hong-Kong University: Dr. X. X. Zhang

Instituto de Química Física “Rocasolano”
Laboratory of Mössbauer Spectroscopy
Consejo Superior de Investigaciones Científicas
Madrid, Spain

Names and Titles of Researchers Dr. José Ramón Gancedo Ruiz – Research Professor Dr. Mercedes Gracia García – Scientist Dr. José Francisco Marco Sanz – Scientist Mr. Carlos Alonso González – Specialized Technician

From left: Carlos Alonso González, Mercedes Gracia García, José Francisco Marco Sanz, and José Ramón Gancedo Ruiz

History and Areas of Research

The Laboratory of Mössbauer Spectroscopy was created in 1973, with the return of Dr. Gancedo from Cambridge (UK), where he had worked three years with Dr. A. G. Maddock, to whom he is deeply indebted. Research facilities were scarce, and so all the equipment but the MCA had to be home-built. Ever since, the main interest of the group has been the study of atmospheric corrosion, mostly of iron. One of the excursions out of this field has been the study of archaeological ceramics, started during the Ph.D. Thesis of Dr. Gracia. With the incorporation of Dr. Marco in 1986, the study of the corrosion of nitride coatings was begun, and CEMS, XPS, and AES were incorporated as standard techniques. Probably the most relevant findings of the group are those concerning the formation of “green rust,” iron sulphite and thiosulphate, and the role played by microcrystalline goethite in the early stages of certain corrosion reactions.

The group collaborates with other Spanish groups working in catalysis, materials science, magnetism, mineralogy, archaeology, etc. The group’s main international cooperations involve Professor F. Berry (The Open University, UK), with frequent stays of Dr. Marco in Professor Berry’s laboratory, and Professor J. L. Gautier (Universidad de Santiago de Chile), in this case for the study of lithium mixed oxides. Bilateral cooperation schemes have been maintained, among others, with Professor P. Gütlich and Dr. W. Meisel (Mainz University, Germany), Dr. D. Hanzel (Josef Stephan Institute, Slovenia), Professor R. Mercader (Universidad de La Plata, Argentina), and Professor A. Morales (Universidad de Medellín, Colombia). Several researchers have received training for CEMS in the group’s laboratories.

Finally, Dr. Gancedo has been a Short Term Expert of the International Atomic Energy Agency, introducing Nuclear Electronic Instrumentation and Mössbauer Spectroscopy in several developing countries.

Universidade de Lisboa
Mössbauer Spectroscopy Laboratory
Synthesis and Electrochemistry of Solids Group
Faculty of Sciences
Lisboa, Portugal

Names and Titles of Researchers Dr. Maria de Deus Carvalho – Member of the Centro de Ciências Moleculares e Materiais (CCMM) and Assistant Professor of the Chemistry and Biochemistry Department, Faculty of Sciences, University of Lisbon Dr. Manuel Rosa Nunes – Member of CCMM and Senior Researcher of the Chemistry and Biochemistry Department, Faculty of Sciences, University of Lisbon Dr. Liliana Ferreira – Member of the Centro de Física da Matéria Condensada da Universidade de Lisboa (CFMC-UL) and Assistant Professor of the Physics Department, Faculty of Sciences and Technology, University of Coimbra

From left: Liliana Ferreira, Maria de Deus Carvalho, and Manuel Rosa Nunes

History and Areas of Research

The Mössbauer spectroscopy laboratory is a facility of the Synthesis and Electrochemistry of Solids (SES) group from the Centro de Ciências Moleculares e Materiais of the Faculty of Sciences, University of Lisbon (FCUL).

Mössbauer spectroscopy was introduced at FCUL by Professor Fernanda Madalena Costa, after finishing her Ph.D. in Leeds, UK (1975) in the area of solid state chemistry. Back in Lisbon, she founded a research group essentially devoted to the synthesis and characterization of oxides with the perovskite and spinel type structures. Under her supervision, several collaborators have benefited from this technique, namely A. C. Santos, M. R. Nunes, M. H. Mendonça, and M. D. Carvalho. The Mössbauer laboratory was renewed by Dr. Manuel Rosa Nunes, who performed important upgrades in the infrastructure and experimental setup. Since 2005, Dr. Maria de Deus Carvalho is responsible for the laboratory and Dr. Liliana Ferreira, member of the CFMC, also from FCUL, is an active collaborator.

The Mössbauer facility at the SES group includes a cryostat and a furnace, allowing measurements from 4 K to 850 K. A Mössbauer conversion electron detector, suitable for surface and thin films studies, is also available.

The main research area involves the study of transition metal oxides with mixed valence, aiming to determine the relation between structure, composition, and their exhibited chemical, magnetic, and electrical properties, covering interests of both chemists and physicists. This project benefits from other CCMM facilities and from the know-how of its members, as well as from members of other Mössbauer groups, namely J. C. Waerenborgh from ITN (Sacavém), the Grupo de Física Nuclear da Matéria Condensada from the University of Coimbra, and A. Wattiaux from the Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), CNRS (France).

Current research activity and collaborations include:

• ⁵⁷Fe doped nickelates Ruddlesden-Popper phases La_n+1Ni_nO_3n+1 (especially n = 2 and n = 3). This project is being performed in collaboration with Dr. A. Wattiaux from ICMCB.

• Oxides with perovskite and brownmillerite type structures, which are potential candidates for electrodes in solid oxide fuel cells (SOFCs). This line of work counts with the collaboration of Dr. J. C. Waerenborgh (ITN).

• Thin films of multifunctional magnetic-half metallic systems doped with iron, in collaboration with CFMC.

Universidad de Córdoba
Química y Electroquímica de Materiales Inorgánicos
Córdoba, Spain

Names and Titles of Researchers Professor Dr. José Luis Tirado – Director Professor Titular Dr. Pedro Lavela Professor Dr. Carlos Pérez-Vicente Dr. Ricardo Alcántara Dr. Gregorio Ortiz Bernardo León Mohedano – Ph.D. Student Mª José Aragón – Ph.D. Student Mª Carmen Mohedano – Technician

Description and Areas of Research

The research group Chemistry and Electrochemistry of Inorganic Materials belongs to the Area of Inorganic Chemistry in the Department of Inorganic Chemistry and Chemical Engineering. It is located at the Campus Rabanales of Córdoba University. The group is officially recognized by the regional government (Junta de Andalucía) as FQM288.

The research work developed in the last years by the group has been bound to the field of lithium, sodium, lithium-ion, and sodium-ion rechargeable batteries. The main activity is centered in the development of new synthesis and electrode design strategies to optimize the electrochemical properties of potential electrode materials, as well as their characterization prior to and during their use in the batteries. The active electrode materials for these types of cells include numerous inorganic compounds, which are studied from the point of view of electrochemistry and material chemistry. Many of them contain Mössbauer nuclei:

• Anode Materials: tin alloys and precursor materials, antimony alloys and precursor materials, transition metal oxides containing iron

• Cathode Materials: metal sulfides with layered and spinel structures containing tin, metal tellurides, layered lithium transition metal oxides, iron-containing spinel-related lithium transition metal oxides, olivine-type lithium iron phosphate

The scientific production in these fields has led to more than 200 published papers in ISI journals. From them, about 50 papers contain results of ⁵⁷Fe, ¹¹⁹Sn, ¹²¹Sb, and/or ¹²⁵Te Mössbauer spectroscopy.

The group has favored the establishment of fruitful collaborations with other European research groups that have allowed an exchange of personnel and ideas. The financial support of this activity has come from six European projects (programs COPERNICO, JOULE2, ENERGY, and MARIE CURIE), some of them coordinated by the University of Córdoba, as well as different national research projects and other bilateral actions (PICASSO program). The different institutions/industries with research collaborations include:

• Equipe Spectrométrie Mössbauer, Laboratoire des Agrégats Moléculaires et Matériaux Inorganiques, Université Montpellier II, France

• Grupo de Materiales Compuestos, Instituto Nacional del Carbón (INCAR), Oviedo, Spain

• Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria

• Surface Science Department, Darmstadt University of Technology, Germany

• Different members of the ALISTORE Network of Excellence

• Industries: SAFT, UMICORE, REPSOL-YPF, Grupo Antolín Ingeniería, S.A.

The research instruments commonly used by the group are related to techniques for materials synthesis and electrode design, materials characterization, and electrochemistry. Among them, the group has ⁵⁷Fe (two lines) and ¹¹⁹Sn Mössbauer spectrometers (AMETEK-WISSEL) and a closed cycle cryostat (CRYOINDUSTRIES).

Instituto de Ciencia de Materiales de Aragón
Laboratorio de Espectroscopía Mössbauer
Consejo Superior de Investigaciones Científicas-Universidad de Zaragoza
Zaragoza, Spain

Names and Titles of Researchers Dr. Javier Rubín – Profesor Titular Dra. Cristina Piquer – Scientist

Cristina Piquer and Javier Rubín

History and Areas of Research

The Mössbauer Spectroscopy Laboratory at the Institute of Materials Science of Aragón is part of a research group working on macroscopic and nanostructured magnetic materials (Group IMANA, lead by Professor Dr. Juan Bartolomé, with nine researchers). It is a new laboratory, commencing its work in October 2005, although its researchers have been related to Mössbauer spectroscopy since 2000. The technical development of the Mössbauer group has benefited from the help of Mössbauer groups from Spain (the Instituto de Química-Física Rocasolano in Madrid and the Department of Electricity and Electronics in Bilbao) and Romania (National Institute for Materials Physics, Bucharest).

The laboratory includes a ⁵⁷Fe source and both standard Mössbauer spectroscopy and CEMS at room temperature. Low-temperature equipment is being set up at present, which will allow for measurements from 15 K.

The research undertaken by Mössbauer spectroscopy includes topics such as (i) rare earth (R)-transition metal intermetallic of the type RFe_11-xM_x (M = 3d, 4d metal) and R_1-xR’_xFe₆Ge₆, (ii) iron-based Laves phases, (iii) antiferromagnetic oxides with perovskite structure, (iv) nanostructured oxided iron films, and (v) magnetic nanoparticles obtained from ferritine.

The current external scientific collaborations related to Mössbauer spectroscopy include:

• Department of Physics, University of Liege, Liege, Belgium: Dr. F. Grandjean

• Department of Solid State Magnetism, National Institute for Materials Physics, Bucharest, Romania: Dr. G. Filoti, Dr. V. Kuncser, and Dr. D. Lazar

• Department of Electricity and Electronics, University of the Basque Country, Bilbao, Spain: Dr. F. Plazaola

• Department of Optical, Magnetic and Transport Properties, Institute of Materials Science of Madrid, Madrid, Spain: Dr. F. Jiménez

Universidade de Coimbra
Mössbauer Laboratory
Nuclear Condensed Matter Physics Group
Department of Physics
Coimbra, Portugal

Names and Titles of Researchers João Gil – Associate Professor Benilde Costa – Assistant Professor Helena Alberto – Assistant Professor

History and Areas of Research

The Mössbauer Laboratory of the Nuclear Condensed Matter Physics Group (Department of Physics, University of Coimbra) was created in 1988 by Professor Nuno Ayres de Campos. Three Ph.D. theses have been done in the group using Mössbauer spectroscopy. Helena Alberto’s thesis in 1995 involved silicate glasses using ⁵⁷Fe Mössbauer spectroscopy in collaboration with the Geophysical Laboratory, Carnegie Institution, Washington, DC, USA. In 1998, Benilde Costa was awarded her Ph.D. thesis in conventional and nanocrystalline FeCrSn alloys using ⁵⁷Fe and ¹¹⁹Sn Mössbauer spectroscopy in collaboration with the Ecole des Mines de Nancy, France. In the following year, Júlia Tovar from the University of Minho (Braga) completed her Ph.D. thesis in rare earth intermetallic compounds using ⁵⁷Fe Mössbauer spectroscopy, in collaboration with the Laboratoire de Cristallographie de Grenoble, France.

Since then, the Mössbauer Laboratory has been used mainly in studies of (i) characterization of samples prepared by mechanical alloying, (ii) phase transformations induced by ball milling, (iii) studies of Debye temperature, and (iv) structural studies of intermetallic compounds with potential use for hydrogen storage.

Some measurements in collaboration with other groups and institutions are also carried out in the Laboratory. The Laboratory has the facility to measure samples from 30 K to 1200 K.

Universidad Autónoma de Madrid
Departamento de Química Física Aplicada
Cantoblanco, Madrid, Spain

Names and Titles of Researchers Professor Jesús Tornero – Group Leader Dra. Nieves Menéndez

History and Areas of Research

During the 1970-1971 academic year, Professor J. Sancho promoted the formation of a new Mössbauer spectroscopy (MS) group in the Universidad Autónoma de Madrid (UAM), which had been created two years before. The group was initially formed by Dr. J. M. Vara and two Ph.D. students, C. Lupiani and J. Tornero, who had stayed several months in the MS laboratory of Professor Adloff in Strasbourg. New Ph.D. students joined the group: H. Alcalá (1974) and N. Menéndez (1986).

The first studies were realized by ¹¹⁹Sn and ⁵⁷Fe Mössbauer spectroscopy and concerned the reactivity in solids and phase transitions in perovskites. Since then, the work in the group has been centered on the structural and magnetic characterization of materials by means of Mössbauer spectroscopy/XRD and to correlate the above-mentioned structures and the properties of materials.

The group’s current research topics include:

• Phase transition in high symmetry compound: Synthesis and growth of monocrystals doped with ⁵⁷Fe to determine its structure by XRD and measurements of crystallographic and magnetic critical parameters by MS.

• Organometallic compounds: Correlations between quadrupole splitting and vibrational Sn-Cl stretching frequencies for octahedral tin(IV) chloride complexes; correlations between isomer shift and the donor atom of the ligands for octahedral tin(IV) chloride complexes; synthesis and characterization of nonstoichiometric spinel ferrites, and nanosized iron oxides and oxyhydroxides.

• Catalysts: Composition, structure, and properties of carbon-supported iron catalysts and Ti_1-xSn_xO₂ photocatalysts.

• Biominerals: Analysis of metal distribution in hyperaccumulator plants with the objective of use in environmental bioremediation.

• Nanostructured materials with technological applications: Preparation and characterization of magnetic nanoparticle thin films; synthesis and characterization of semiconductors doped with transition and rare earth ions for their applications on spintronics and optoelectronics.

The group’s facilities include the following equipment:

• Three Mössbauer spectrometers with ⁵⁷Fe and ¹¹⁹Sn sources

• One CEMS detector for room-temperature measurements

• Eight Tesla superconducting coils, parallel and perpendicular to the gamma radiation, for measurements between 1.5 up to 300 K

• Two Mössbauer cryostats for measurements from 4.5 or 77 K up to 300 K and one furnace for measurements from RT to 1000 K

The research group has active collaborations with several research institutions:

• Departamento de Rayos X, Instituto Rocasolano, CSIC: Professors J. Fayos, F. H. Cano, and M. Martínez-Ripoll

• Departamento de Química Inorgánica, Universidad Autónoma de Madrid: Professor V. Fernández and Dr. D. Tudela

• Departamento de Química Inorgánica, Universidad Complutense de Madrid: Professors E. Morán and M. Cano

• Instituto de Magnetismo Aplicado (RENFE-UCM): Professor A. Hernando and Dr. P. Crespo

• Instituto de Ciencia de Materiales de Madrid: Professor J. L. Martínez and Drs. M. García-Hernández and C. Prieto

• Centro de Biología Molecular, Universidad Autónoma de Madrid: Professor R. Amils and Dr. V. de la Fuente

Universidad Autonoma de Madrid
Thin-Layer and Surface Physics Group
Centro de Micro-Análises de Materiales (CMAM)
Cantoblanco, Madrid, Spain
http://www.uam.es/otroscentros/cmam/

Ewelina Andrzejewska

Names and Titles of Researchers Professor Dr. Dirk Boerma – Group Leader Dr. David Martin – Senior Researcher Dr. José Emilio Prieto – Senior Researcher Dr. Antonio Ribera – Senior Researcher Angel Guirao – Technical Engineer Ewelina Andrzejewska – Ph.D. Student Roch Andrzejewski – Ph.D. Student Nuria Gordilla – Ph.D. Student

Description and Areas of Research

The Centre for Micro-analysis of Materials (CMAM), inaugurated in 2002, is a part of the Universidad Autónoma de Madrid and is supported by the Parque Científico de Madrid. The main research tool of the Centre is a 5 MV Tandem accelerator, used for ion beam analysis and ion beam modification of thin layers. The Thin-Layer and Surface Physics Group of the Centre is doing fundamental and applied research on the synthesis, structure, and properties of functional thin (multi-) layers, including nano-patterned layers. Conversion electron Mössbauer spectroscopy (CEMS) is used by this group as an additional tool for investigating ⁵⁷Fe-containing layers. The combination of CEMS with advanced instrumentation at the 5 MV tandem accelerator for depth profiling and determination of structures, including atom sites, is providing promising research opportunities. The instrumentation includes:

• A setup equipped with a position sensitive time-of-flight detector for surface analysis (structure and composition) with low-energy ion scattering/recoiling (LEIS-TOF). In this system (epitaxial), layers of metals, nitrides, and oxides can be grown and characterized with LEIS, LEED, and RBS/Channelling.

• A magnetic spectrograph of a special design, allowing the measurement of ions scattered or recoiled into a large solid angle of 7º x 9º with an angular resolution of 0.2º. The relative energy resolution of 10^-3 allows depth profiling of both light and heavy elements with a depth resolution of a few mono-layers, and the simultaneous recording of blocking patterns.

• A facility to collimate and focus ion beams from the accelerator to dimensions of about 20 nm. This facility will be used as a proton microscope.

• A setup for conversion electron Mössbauer spectrometry (CEMS) for ⁵⁷Fe.

The main science projects on (multi-)layer systems with possible applications as device materials are waiting for the completion of the infrastructure in 2006. In the meanwhile, experimental work is being executed on Fe nitrides. The group has been able to grow epitaxial thin films of the different phases of iron nitrides (γ´-Fe₄N, γ´´-FeN, ε-Fe_2-3N) in their pure form, with the exception of α´´-Fe₁₆N₂,. This phase, which is reported to possess the highest saturation magnetization known, was grown with a degree of purity of 30-40%. Films of the different phases were characterized by different techniques, including CEMS, RBS, optical Kerr effect, and X-ray magnetic dichroism. In collaboration with the Catholic University of Leuven, Belgium, the group is trying to theoretically reproduce the measured Mössbauer parameters.

Universidad de Sevilla
Group of Non-Crystalline Solids
Departamento de Física de la Materia Condensada
Sevilla, Spain

Names and Titles of Researchers

• Dr. Alejandro Conde – Professor (Group Leader)

• Dr. Clara F. Conde – Professor

• Dr. Josefa M. Borrego – Associate Professor

• Dr. Victorino Franco – Associate Professor

• Dr. Juan Leal – Associate Professor

• Dr. María Millán – Associate Professor

• Dr. Javier S. Blázquez – Scientist

• Mr. Jhon J. Ipus – Ph.D. student

History and Areas of Research

The Non-Crystallline Solids Group at the University of Seville, originally created in the early 1980s, set up its ⁵⁷Fe Mössbauer facility (with a furnace in vacuum) about two years ago. The lab’s contact with Mössbauer spectroscopy came along about 10 years before the acquisition of the spectrometer, in cooperation with the Laboratory of Mössbauer Spectrometry of the Universidad Nacional de San Marcos, Lima (Perú), and Laboratoire de Physique de L’Etat Condensé, Université du Main, Le Mans (France).

The main research interest in the last few years concerns Fe- and FeCo-based soft magnetic amorphous and nanocrystalline alloys, multicomponent Fe-based soft magnetic amorphous alloys with very high glass forming ability, and powder samples prepared by ball milling.

On-going projects include the study of:

• Structural relaxation phenomena previous to crystallization

• Thermal stability of the amorphous and nanocrystalline phases and kinetics of the glass transition and the crystallization process

• Microstructural characterization correlating results from different experimental techniques

• Correlation between microstructure and magnetic properties

• Study of the superparamagnetism and the influence of interactions between nanoparticles

• Analysis of the magnetic anisotropy distribution

• Magnetocaloric effect

Besides Mössbauer spectroscopy, the group combines structural characterization techniques (X-ray diffraction and electron microscopy), magnetic characterization techniques (hysteresis loop trazer and vibrating sample magnetometry) and thermal characterization techniques (differential scanning calorimetry and thermomagnetic gravimetry). The group also has a ball milling planetary equipment and an arc-melting furnace for sample preparation.

Mössbauer spectrometry has allowed the group to obtain important conclusions on the biphasic system nanocrystal-intergranular amorphous phase of the nanocrystalline alloys:

• The non-uniformity of the intergranular phase resulting from the diffusion process involved in the nanocrystal’s growth.

• The combined used of X-ray diffraction and Mössbauer spectroscopy leads to an estimation of the thickness of interface region and the compositions of both the nanocrystalline and the residual amorphous phases.

• The influence of both compositional changes and ordered/disordered structure on hyperfine parameters of the nanocrystalline phase discussed in terms of a binomial distribution and nearest-neighbour approximation.

In the last few years, the group has had scientific collaboration with:

• Laboratory of Mössbauer Spectroscopy of the Universidad Nacional de San Marcos, Lima, Perú: Dr. V. Peña-Rodríguez

• Laboratoire de Physique de L’Etat Condensé, Université du Main, Le Mans, France : Dr. J. M. Greneche

• Leibniz Institut für Metallische Werkstoffe, IFW Dresden, Germany: Dr. J. Eckert and Dr. S. Roth

• Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland: Dr. T. Kulik

• Department of Metal Physics, Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia: Dr. P. Svec

• Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest, Hungary: Dr. L. Kiss

Universidade do Porto
IFIMUP (Institute of Physics of Materials)
Departamento de Física
Porto, Portugal

Names and Titles of Researchers Dr. David Schmool – Head of Facility, Assistant Professor Dr. Manuela Amado – Assistant Professor Dr. Maria de Alegria Feio – Assistant Professor

David Schmool

Description and Areas of Research

The group possesses a ⁵⁷Fe Mössbauer spectrometer using both transmission and conversion electron geometries. Currently, they work at room temperature and have a furnace system that allows transmission measurements to be made from room temperature up to 1000 K. The group hopes to install a low vibration closed cycle cryostat in the near future to expand the measurement range down to 4 K. They also have the capabilities to measure spectra in the presence of magnetic fields of up to 0.5 T.

In previous work, the group has studied the system Fe_xAl_1-x in the range 0.85 ≥ x ≥ 0.695, using room temperature transmission Mössbauer spectroscopy, in conjunction with ferromagnetic resonance and X-ray diffraction. Samples in this study were produced by the melt-spinning technique and are in ribbon form. While the x = 0.85 sample is purely ferromagnetic in nature, the samples undergo a gradual reduction in magnetization with decreasing x, followed by an abrupt transition to superparamagnetic behavior in the vicinity of x = 0.7. A microscopic study reveals that from the x = 0.85 sample, the ferromagnetic network is gradually broken up into small ferromagnetic clusters, and the x = 0.7 sample is composed by ferromagnetic clusters surrounded by a paramagnetic matrix. In future Mössbauer measurements the group plans to investigate the properties of iron oxides of various systems (garnets and spinels) and alloys of FeSiB.

The group has strong collaborational links with the Mössbauer group of the Departamento de Fisica Aplicada (Dr. J. S. Garitaonandia) and Electricidade y Electronica (Professor F. Plazaola) of the University of the Basque Country in Spain.

Universitat Politècnica de Catalunya
Metastable and Nanostructured Materials
Campus Baix Llobregat
Castelldefels, Barcelona, Spain

Names of Researchers Dr. Daniel Crespo Dr. Trinitat Pradell Dr. Eloi Pineda Dr. Nativitat Salvadó Dr. Salvadó Butí Mr. Pere Bruna Mr. Victor Garrido Mr. Josep Rojas

Areas of Research

Metallic Glasses: Stability and Kinetics of Microstructural Development

• Modeling of the thermodynamics and kinetics of phase transformations, determination of grain size distributions as a function of the kinetic parameters (nucleation and growth rates), kinetic mechanisms of primary transformations

• Scattering properties of nanostructured materials, application to the analysis of neutron and X-ray  Small Angle Scattering (SANS and SAXS), modeling

• Production, characterization, and stability of metallic glasses

• Characterization, thermal stability, and crystallization of nanostructured and amorphous materials obtained by means of fast cooling and mechanical alloying

• Production and optical and electrical properties of metal-glass nanostructured thin layers

Studies of Materials of Interest in Cultural Heritage

• Ceramics: Characterization, conservation

• Metastable materials (glasses, glazes, and opacifiers): Characterization, production techniques, stability, degradation, and historical evolution

• Paintings (pigments, binders): Characterization, stability, and conservation, identification of reaction, aging, and degradation compounds

The group’s national and international collaborations include:

• Universitat Autonoma de Barcelona

• Universitat de Girona

• SRS Daresbury Laboratory

• ESRF

In 2001, the group established a Memorandum of Understanding with the CCLRC-SRS, Daresbury Laboratory, to promote the application of synchrotron radiation to the study of ancient materials.

Universidade Tecnica de Lisboa
Mössbauer Laboratory
Department of Physics
Instituto Superior Técnico de Lisboa
Lisboa, Portugal

Names and Titles of Researchers Mircea Serban Rogalski, Ph.D. – Associate Professor José Mariano – Ph.D. Student Ana Taborda – Ph.D. Student

Mircea Serban Rogalski

Description and Areas of Research

Mössbauer spectroscopy studies have been performed in the last years at the Instituto Superior Técnico in Lisbon in the frame of interdisciplinary research on synthesis and characterisation of thin magnetic films and heterostructures together with the modelling of their structure and surface/interface properties. ⁵⁷Fe transmission and conversion electron Mössbauer spectroscopy, together with ⁵⁹Co NMR techniques, were applied to study:

• Magnetic nanostructures deposited by CVD, laser ablation, and magnetron sputtering

• The effect of corrosion inhibitors on carbon steel

Currently, Mössbauer studies on magnetite layers grown by magnetron sputtering are used for the development of heterostructures with half-metallic Fe₃O₄ of high spin polarization.