Reprinted from the March 2002 edition of the Mössbauer Spectroscopy Newsletter, published as part of Volume 25, Issue 3 of the Mössbauer Effect Reference and Data Journal
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Mössbauer Spectroscopy in the Republic of Korea |
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In the response to a general call for information on the current Mössbauer research that is taking place in the Republic of Korea, the following reports were received by the Mössbauer Effect Data Center.
Mössbauer and Nano Magnetic Materials Laboratory
Kookmin University
Seoul, Republic of Korea
Names and Titles of Researchers
Dr. Chul Sung Kim – Head of the Laboratory
Dr. In Bo Shim – Staff
Dr. Sam Jin Kim – Research Professor
Dr. Sung Baek Kim – Post-Doctoral Research Associate
Geun Young Ahn – Ph.D. Student
Hi Min Lee – Ph.D. Student
Sang Won Lee – Ph.D. Student
Hong Joo Ryu – M.S. Student
Bong-Yeon Won – M.S. Student
Dong Hyeok Choi – M.S. Student
Jun Sik Keum – M.S. Student
Kang Ryong Choi – M.S. Student
Bo Ra Myoung – M.S. Student
Jin Ok Kim – M.S. Student
History and Areas of Research
Dr. Chul Sung Kim heads the Mössbauer and Nano Magnetic Materials Laboratory at the Kookmin University of Korea. He has been analyzing various kinds of materials using Mössbauer spectroscopy for over 20 years, including oxide-ferrites, sulfur spinels, perovskites, and magnetic semiconductors. Current Mössbauer studies at Kookmin University focus on nanoparticles, magnetic multilayers, magnetic oxides, and nanobiomagnetic materials. A major current study is on magnetic exchange interaction, hyperfine field fluctuation, charges, and spin transport phenomena in nanoscale materials. He continuously collaborates with other faculty and scientists as research ideas are developed in the general area of materials science. Below is a list of Mössbauer collaborators:
Dr. Bo Wha Lee, Physics Professor, Hankuk University of Foreign Studies, Korea
Dr. Kwang-Deog Jung, Dr. Y. J. Oh, Dr. S. H. Lim, and Dr. H. J. Kim, Korea Institute of Science and Technology, Korea
Dr. Taeg Hwan Hyeon, Chemical Engineering Professor; Dr. Hwan Kim, Professor at the School of Material Science and Engineering; Dr. Man Soo Choi, Professor at the School of Mechanical and Aerospace Engineering, Seoul National University, Korea
The Mössbauer and Nano Magnetic Materials Laboratory at Kookmin University is equipped with three kinds of absorption-type spectrometers, a conversion electron Mössbauer spectrometer, and an external Mössbauer spectrometer. Synthesis of films and powder samples are done using various methods, e.g., direct reaction method, sol-gel driven method, sputtering method, and pulsed laser deposition. Experimental investigations of the physical properties of the materials are performed using various procedures, e.g., X-ray, TG-DTA, FT-IR measurement, magnetic measurements (VSM, SQUID), microscope images (AFM, SEM, TEM), magnetoresistance measurement, neutron diffraction, and EPR.
The Laboratory’s ongoing research covers five areas:
Ferrite materials: Co-ferrite, Ba-hexa ferrite, and Garnet ferrite of thin films and powder are studied with MS, CEMS, magnetization measurements, and X-ray diffraction. The study aims to investigate nanocrystal structures and magnetic properties in as many transition metal complex systems as possible in order to check the scale magnetic interaction limit. This study will then be expanded to more complex systems.
Colossal magnetoresistance of transport oxide materials: Conduction mechanisms of Mn perovskite oxide and double perovskite with iron doping are determined using magnetoresistance, MS, and neutron diffraction technique. Physical interpretations of the CMR mechanism in these materials are obtained using various methods, e.g., magnetic hyperfine filed fluctuation model, field distribution, charge ordering, and Jahn-Teller mechanism. This study will then be expanded according to the new interpretation in these materials.
Magnetic semiconductor materials: Co-Ti oxide and Cr oxide systems are studied for magnetic semiconductor device, along with its possible applications. The main research topics are the spin injection and tunnel type carrier transport. The study aims to determine the effect of RKKY interaction and magnetic dilution problem on these systems in relation to the crystal structure and doping materials.
Fe-(Si, Al)-Nb-B-Cu nanocrystalline systems: Nanocrystalline for the Fe-(Si, Al)-Nb-B-Cu alloy is studied with MS and XRD. Magnetic exchange interaction and hyperfine filed distribution and amorphous properties are studied on the basis of various kinds of models. The study aims to enhance magnetic permeability with little energy lost when these materials are used for soft magnetic devices.
Sulfur spinel materials: The magnetic, structural, and transport properties of sulfur spinel complexes are explored with MS, neutron diffraction refinement, and conductivity measurements. The study aims to determine which characteristics are essential for the main mechanism of magnetism and electron transport phenomena. Renewal interests are focused on these complexes for magnetic semiconductor. The half-metallic properties and the role of the dynamic Jahn-Teller effect on these materials are studied.
Yonsei University
Seoul, Republic of Korea
Names and Titles of Researchers
H. N. Oak – Director, Professor
K. S. Baek – Professor
E. J. Choi – Associate Professor
D. H. An – Student
K. U. Kang – Student
B. G. Lee – Student
J. B. Lim – Student
Areas of Research
Superexchange interactions, atomic migration, crystallographic, and spin-rotation transitions in various magnetic materials are being investigated with special emphasis on both bulk and nano-size ferrites and chalcogenides.
Korea Institute of Science and Technology
Seoul, Republic of Korea
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Names and Titles of Researchers Dr. Young-Jei Oh – Group Leader |
Dr. Young-Jei Oh |
Areas of Research
The group at the Korea Institute of Science and Technology has studied ferrites, colossal magnetoresistance (CMR) ceramic materials, dilute magnetic semiconductors (DMS), dielectric and ferroelectric materials. Research includes the basic science of materials to understand their relation to structures and properties. The group focuses on the fabrication and characterization of thin films by pulsed laser deposition (PLD) and the sol-gel method, thick films by screen printing, ceramic sheets by the Dr. Blade method, and synthesis of nano-size ceramic powders by the cryochemical process. Some ceramic sensors are also developed and commercialized.
Yeungnam University
Kyongsan, Kyongbuk, Republic of Korea
Names and Titles of Researchers
Eng Chan Kim – Director, Professor
Jong Soo Han – Doctor Course
Kyung Soo Kim – Graduate Student, Ph.D. Course
Jin Eui Kim – Graduate Student, Ph.D. Course
Jae ho Shin – Graduate Student, M.A. Course
Su ho Moon – Graduate Student, M.A. Course
Seung il Woo – Graduate Student, M.A. Course
Jae Suk Yang – Post-Doctoral Research Associate
Se Joo Kim – Undergraduate Student, B.A. Course
Areas of Research
The laboratory at Yeungnam University researches the magnetic and crystallographic properties of various magnetic materials with a Mössbauer spectrometer, an X-ray diffractometer, a SQUID magnetometer, and a vibrating sample magnetometer. The main research thesis is related to spinel ferrites, the ferrimagnetic materials. In the spinel ferrite there exists an atomic migration phenomenon between the A (tetrahedral) site and the B (octahedral) site by the external variation of temperature, pressure, and magnetic properties. The site distribution of magnetic atoms has been examined from the study of the atomic migration phenomenon. In addition, superexchange interaction in spinel ferrites is examined by the calculation of the integral constant. Recently, the research group has undertaken an interest in magnetic thin film materials, especially the nanocomposite magnet with conversion electron Mössbauer spectrometry (CEMS).
Wonkwang University
Jeonbuk, Republic of Korea
Names and Titles of Researchers
Jung Chul Sur – Director
Dae Seong Kim – Student
Ho Seon Lee – Student
Sea Jung Kim – Student
Min Yong Lee – Visiting Scientist
Young Bok Ko – Visiting Scientist
Areas of Research
The research group at Wonkwang University is working in the following areas:
Fabrication of magnetic thin films by pulsed laser and sputtering systems
Crystallographic and magnetic properties of nano-size magnetic particles
Conversion electron Mössbauer studies of multi-layered thin films
Electronic and magnetic properties in CMR
Spin fluctuation in magnetic fine particles
Crystallographic and magnetic properties of sulfur spinels
Hanyang University
Seoul, Republic of Korea
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Names and Titles of Researchers Jung Gi Kim – Professor |
Areas of Research
The group at Hanyang University is researching the magnetic properties and phase transition of:
Nanostructured gamma-Ni-Fe alloys synthesized by a mechanochemical process
(Fe, M, BN) (M = metal) alloy sheets
Nanostructured hematite synthesized sol-gel process
Mixed crystalline (Eu2O3)x(Fe2O3)1-x
Additional items of interest include controlling the crystallographic orientation in ultrathin FePt(111) films on MagO(111) underlayer and magnetic and microstructural properties of alloy films [(Fe,N), (Fe,M,BN or N)....] (M = metal).
Dongguk University
Seoul, Republic of Korea
Names and Titles of Researchers
Hyung-sang Kim – Director-Department of Physics, Associate Professor
Sun-bae Kim – Ph.D. Student
Tae-hyun Yang – Ph.D. Student
Il-ku Kiim – Ph.D. Student
Sang-hoon Rhu – Masters Student
Seung-su Baek – Masters Student
Tae-hee Kim – Masters Student
Areas of Research
The group at Dongguk University is, among other things, studying properties in magnetism, the metastable state in single crystals (SNP), properties of Fe in biology, and the properties in nuclear reactor vessels.
Cheju National University
Cheju, Republic of Korea
Names and Titles of Researchers
Sung-Rak Hong – Professor
Jeong-Dae Ko – Professor
Tae-Gun Yoon – Student
Won-Jun Choi – Student
Soo-Young Boo – Student
Areas of Research
The group at Cheju National University is studying ferrite materials, ancient plain coarse pottery, and scoria and volcanic rock in Jeju Island. It utilizes Mössbauer spectrometers (Fe-57, two systems), VSM, AFM, XRD, XRF, and XPS for these studies. Recently the group has undertaken an interest in CMR and crystallographic structure in diluted magnetic semiconductor as GaFeAs, GaFeN.