• Title/Summary/Keyword: M$\ddot{o}$ssbauer 분광법

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The Thermal Dynamics of Fe Ion on the M-type Ba-ferrite (M형 Ba-Ferrite에서 Fe 이온의 열 진동에 관한 연구)

  • Sur, Jung-Chul;Ghim, Jin-Soo;Choi, Jong-Wan
    • Journal of the Korean Magnetics Society
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    • v.21 no.1
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    • pp.5-9
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    • 2011
  • M$\ddot{o}$ssbauer and Raman spectrum studies have been carried out on the 2b-site Fe ion in the Ba-ferrite (M-type). The thermal dynamics of Fe ion was analyzed by M$\ddot{o}$ssbauer spectra at different angles between the $\gamma$-ray direction and c-axis. The vibration on the 2b-site was more active compare to other direction and had very strong intensity in the Raman spectrum.

Study of the Nondestructive Test Method for the Embrittlement Evaluation of Nuclear Reactor Vessel Material by $M{\ddot{o}}ssbauer$ Spectroscopy ($M{\ddot{o}}ssbauer$ 분광법에 의한 원자로 용기재료의 비파괴적 중성자 조사평가에 대한 연구)

  • Jung, M.M.;Jang, K.S.;Yoo, K.B.;Kim, G.M.;Yoon, I.S;Hong, C.Y.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.3
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    • pp.183-190
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    • 2000
  • The purpose of this study is to evaluate the magnetic property change of the nuclear reactor vessel steel irradiated by fast neutrons using $M{\ddot{o}}ssbauer$ spectroscopy, and the effects of the defects produced by neutron irradiation on the changes using X-ray diffraction. The specimens, fabricated with the dimension of $23mm{\times}18mm{\times}70{\mu}m$, were irradiated by neutron fluence from $10^{12}n/cm^2\;to\;10^{18}n/cm^2$ at 343K. Throughout the experiments, it is understood that (1) the X-ray diffraction measurement shows that the change of crystal nature is started at the irradiation of $10^{16}n/cm^2$ and a crystal structure has been severely damaged at the irradiation over $10^{17}n/cm^2$, (2) the analysis of the $M{\ddot{o}}ssbauer$ spectra has shown that magnetic transition phenomena occur at the irradiation over $10^{17}n/cm^2$ and (3) both methods can be utilized as nondestructive test methods for the embrittlement evaluation of materials irradiated by fast neutrons.

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The Preparation and Magnetic Properties in Ba-ferrite Film on the A12O3 Substrate (A12O3을 하지층으로 하는 Ba-ferrite 박막의 제조 및 자기적 특성에 관한 연구)

  • Sur, Jung-Chul;Park, Chul-Jin;Choi, Jung-Wan
    • Journal of the Korean Magnetics Society
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    • v.15 no.2
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    • pp.125-129
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    • 2005
  • Ba-Ferrite thin films were prepared on $A1_2O_3$ substrate by a pulsed laser deposition system and characterized by SEM, $M\ddot{o}$ssbauer spectroscopy and VSM. The appropriate conditions of pulsation in Ba-ferrite was the oxygen pressure of 0.1 Torr at a substrate temperature of $400^{\circ}C$ and the thickness was variable with the deposition time. Ba-ferrite crystals had the forms of hexagonal plate in the 5 minute deposited film and the needle grains coexisted with the increasing film thickness. $M\ddot{o}ssbauer$ spectroscopy assured that the direction of atomic spin in Fe ion tends to normal to the substrate in the hexagonal plate. The VSM curves have the two types hysteresis of hexagonal and needle phase.

Crystallographic and Magnetic Properties of the Ferrimagnetic $Fe_7Se_8$ by M$\ddot{o}$ssbauer Spectroscopy (뫼스바우어 분광법에 의한 준강자성체 $Fe_7Se_8$의 결정학적 특성 및 자기적 특성)

  • 조용호;김효준;이동욱;김응찬;남효덕
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.1
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    • pp.62-66
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    • 1998
  • M$\ddot{o}$ssbauer spectra of ferrimagnetic $Fe_2SE_8$ prepared with $^{57}Fe$ enriched iron have been taken at 298 K and below 78K, and Fe\ulcornerSe\ulcorner has been studied by X-ray diffraction. The crystal structure is found to be a "3c" hexagonal superstructure of the NiAs structure. Three sets of six-line hyperfine patterns were obtained and assigned to three magnetically nonequivalent sites of a superstructure of the crystal. The iron ions at all three sites are found to be in a highly covalent ferrous state. It is shown that the results obtained at the low temperature region are well consistent with Okazaki's "3c" superstructure model.uperstructure model.

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The Magnetic Properties of Iron Compounds of the Scoria in North-Eastern Area of Jeju Island (제주도 북동부 지역 스코리아 내의 철 화합물에 대한 자기적 성질)

  • Ko, Jeong-Dae;Choi, Won-Jun
    • Journal of the Korean Magnetics Society
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    • v.21 no.1
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    • pp.37-41
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    • 2011
  • Fe compounds of scoria samples distributed in Songdang-ri positioning north-eastern area of Jeju island were investigated by means of X-ray diffractometry (XRD) and $^{57}Fe$ M$\ddot{o}$ssbauer spectroscopy. The samples were prepared from six parasite. We found that the samples were composed of a typical olivine, pyroxene, ilmenite, $SiO_2$, anorite and anorthoclase, M$\ddot{o}$ssbauer spectrum of the most scoria samples are shown doublets and sextets of olivine, doublets of pyroxene, ilmenite and silicate minerals. And the valence states of Fe ion of the scoria samples in this area are chiefly 3+ charge state and a little 2+ charge state.

Mössbauer Studies of CoGa0.1Fe1.9O4 Nanoparticles (나노분말 CoGa0.1Fe1.9O4의 Mössbauer 분광학적 연구)

  • Lee, Seung-Wha
    • Journal of the Korean Magnetics Society
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    • v.16 no.2
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    • pp.144-148
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    • 2006
  • $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticles have been prepared by a sol-gel method. The structural and magnetic properties have been investigated by XRD, SEM, VSM and $M\ddot{o}ssbauer$ spectroscopy. $CoGa_{0.1}Fe_{1.9}O_4$ powder that was annealed at $250^{\circ}C$ has spinel structure and behaved superparamagnetically. The estimated size of superparammagnetic $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle is around 10 nm. The hyperfine fields at 4.2 K f3r the A and B patterns were found to be 518 and 486 kOe, respectively. The blocking temperature $(T_B)$ of superparammagnetic $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle is about 250 K. The magnetic anisotropy constant of $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle was calculated to be $3.0X10^5\;ergs/cm^3$. $CoGa_{0.1}Fe_{1.9}O_4$ nanoparticle was annealed at $250^{\circ}C$ will be used to candidate for biomedicine applications as magnetic carriers.

Superparamagnetic Properties of MnFe2O4 Nanoparticles (초미세 나노분말 MnFe2O4의 초상자성 성질 연구)

  • Lee, Seung-Wha;Lee, Jae-Gwang;Chae, Kwang-Pyo;Kwon, Woo-Hyun;Kim, Chul-Sung
    • Journal of the Korean Magnetics Society
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    • v.19 no.2
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    • pp.57-61
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    • 2009
  • $MnFe_2O_4$ nanoparticles have been prepared by a sol-gel method. The structural and magnetic properties have been investigated by XRD, SEM, and $M{\ddot{o}}ssbauer$ spectroscopy, VSM. $MnFe_2O_4$ powder that was annealed at $250^{\circ}C$ has spinel structure and behaved superparamagnetically at room temperature. $MnFe_2O_4$ annealed at 400 and $500^{\circ}C$ has a typical spinel structure and is ferrimagnetic in nature. The estimated size of superparammagnetic $MnFe_2O_4$ nanoparticle is around 17 nm. The hyperfine fields of the A and B patterns at 4.2 K were found to be 508 and 475 kOe, respectively. The blocking temperature ($T_B$) of superparammagnetic $MnFe_2O_4$ nanoparticle is about 120 K. The magnetic anisotropy constant and relaxation time constant of $MnFe_2O_4$ nanoparticle were calculated to be $4.9{\times}10^5erg/cm^3$.

A Study on Iron Compounds of Scoria in Mid Mountain Area of Jeju (제주 중산간지역 스코리아의 철 화합물에 관한 연구)

  • Choi, Won-Jun;Ko, Jeong-Dae
    • Journal of the Korean Magnetics Society
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    • v.17 no.5
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    • pp.205-209
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    • 2007
  • It have been investigated the measured results of the XRF, the X-ray diffractometry and $^{57}Fe\;M{\ddot{o}}ssbauer$ spectrum for scoria samples which are distributed throughout different areas in Mid-mountain Area of Jeju island. We consider that the scoria samples are chiefly made of silicate minerals, like $SiO_2$, others silicate minerals and iron oxides minerals. We study that it's materiel is consisted of olivine, pyroxene, ilmenite, hematite and magnetite. Iron compounds in that are $Fe^{2+}$ of olivine, pyroxene, ilmenite and $Fe^{3+}$ of hematite, magnetite et al. The major Fe fractions of the scoria samples are 51.77 wt%, so Fe fractions of the scoria samples are almost 3+ charge state with a little of the 2+ charge state.

Mössbauer Studies on Magnetoresistance in Chalcogenide Fe0.9M0.1Cr2S4 (M=Co, Ni, Zn) (Chalcogenide Fe0.9M0.1Cr2S4(M=Co, Ni, Zn)의 자기저항에 관한 Mössbauer 분광연구)

  • Park, Jae Yun;Lee, Byoung-Seob
    • Journal of the Korean Magnetics Society
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    • v.23 no.2
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    • pp.43-48
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    • 2013
  • The Jahn-Teller distortion of chalcogenide $Fe_{0.9}M_{0.1}Cr_2S_4$ (M=Co, Ni, Zn) have been investigated by M$\ddot{o}$ssbauer spectroscopy. The crystal structures of $Fe_{0.9}M_{0.1}Cr_2S_4$ (M=Co, Ni, Zn) are cubic spinel at room temperature. Magnetoresistance measurements indicate these system is conducting-semiconducting transistion around $T_C$. Below $T_C$, the asymmetric line broadening is observed and considered to be dynamic Jahn-Teller distortion. Isomer shift value of the samples at room temperature was about 0.5 mm/s, which means that charge state of Fe ions is ferrous in character. The Ni substitutions for Fe occur to increase the Jahn-Teller relaxation. CMR properties could be explained with magnetic polaron due to Jahn-Teller effect, which is different from both the double exchange interactions of manganite system and the triple exchange interactions of chalcogenide $Cu_xFe_{1-x}Cr_2S_4$.

Mössbauer Spectroscopic Study on Colorative Mechanism of Celadon Glaze (청자 유약 발색메카니즘에 대한 뫼스바우어 분광법에 의한 연구)

  • Kim, Jong-Young;No, Hyung-Goo;Jeon, A-Young;Kim, Ung-Soo;Cho, Woo-Seok;Kim, Kyung-Ja;Kim, Chin-Mo;Kim, Chul-Sung
    • Journal of the Korean Ceramic Society
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    • v.48 no.1
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    • pp.34-39
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    • 2011
  • Systematic study on relationship between celadon coloring and glaze component was conducted by chromaticity analysis and M$\ddot{o}$ssbauer spectroscopic analysis. The chromaticity ($L^*$, $a^*$, $b^*$ values) and M$\ddot{o}$ssbauer analysis results were correlated to the amount of $Fe_2O_3$, $TiO_2$, MnO, and $P_2O_5$, which are the essential factors influencing celadon coloring. According to chromaticity analysis, celadon glaze color belongs to GY group when the addition of $TiO_2$ was 1.4%, whereas the color belongs to BG group when the addition of $TiO_2$ was 0.1%. For the GY group, the colors change from GY to YR with the decrease of brightness as the addition of $TiO_2$, MnO, and $P_2O_5$ increases. According to M$\ddot{o}$ssbauer analysis results, as the amount of divalent iron ion increases, the $a^*$ and $b^*$ values decrease, on the other hand, $L^*$ value increases. The ratio of divalent iron ion produced in reductive sintering process is found to be 80~95% in this study, which induces the increase of $L^*$ values in celadon glaze.