Magnetotransport and magnetic properties of sulfospinels Zn
x
Fe1?x
Cr2S4 |
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Authors: | Jae Yun Park Kwang Joo Kim |
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Institution: | (1) Department of Materials Science and Engineering, University of Incheon, Incheon, 402-749, South Korea;(2) Department of Physics, Konkuk University, Seoul, 143-701, South Korea |
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Abstract: | Cr-based chalcogenide spinels, which do not have heterovalency and distortion-induced ions such as manganese oxides with perovskite structure, have demonstrated the existence of colossal magnetoresistance. In order to investigate the magnetotransport phenomena and magnetic properties of sulfospinels Zn x Fe1?x Cr2S4, polycrystalline Zn x Fe1?x Cr2S4 samples were synthesized in the 0?≤?x?≤?0.2 range by a solid reaction method. The crystal structure for x?=?0.05, 0.1, and 0.2 turned out to be cubic at room temperature by X-ray diffraction measurement. In magnetoresistance measurement, Zn x Fe1?x Cr2S4 samples indicate that this system is semiconducting below about 150 K. The temperature of maximum magnetoresistance is almost consistent with Curie temperature. The isomer shift and the electric quadrupole shift of Zn x Fe1?x Cr2S4 samples by Mössbauer experiment show that Fe2+ ions occupy the tetrahedral site in the spinel structure. As the Zn ions are substituted for Fe ions, the Jahn–Teller relaxation slows down and the electric quadrupole shift increases. The magnetotransport phenomena of Zn x Fe1?x Cr2S4 is related to Jahn–Teller effect and half-metallic electronic structure, which are different from the double exchange interactions of the manganite La–Ca–Mn–O system or the triple exchange interactions of sulfospinel Cu x Fe1?x Cr2S4. |
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Keywords: | sulfospinel magnetotransport M?ssbauer spectroscopy |
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