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Magnetic Properties and M（?）ssbauer Spectroscopy of Charge-ordering Manganite Y0.5Ca0.5MnO3

Author: TianHongWei
Tutor: ZhengWeiTao；DingTao
School: Jilin University
Course: Materials Physics and Chemistry
Keywords: Perovskite manganite Charge ordering Electron paramagnetic resonance Mossbauer spectroscopy
CLC: TB39
Type: PhD thesis
Year: 2005
Downloads: 297
Quote: 0
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Abstract


The giant magnetoresistance effect in the perovskite -type manganese oxide , the charge - ordered state and phase separation phenomena become a research focus in the current materials science and condensed matter physics . Meanwhile, the system is highly correlated strongly correlated electron system of the charge, spin, lattice and orbital degrees of freedom , bears very rich physical content , comparable to copper-oxide high-temperature superconductors . Therefore , the thesis of the typical charge ordered of manganese oxide Y0.5Ca0.5MnO3 material preparation and characterization of the study , made ??some valuable research . The authors used the traditional high-temperature solid - state reaction method prepared polycrystalline sample of Y0.5Ca0.5MnO3 and iron doped Y0.5Ca0.5Mn0.9Fe0.1O3 , the structure of the samples were characterized by X-ray diffraction (XRD) ; adopt superconducting Quantum Interference Devices (SQUIDS) study the macroscopic magnetic properties of polycrystalline samples ; means of electron paramagnetic resonance and Mossbauer spectroscopy experiments on samples microscopic magnetic properties and charge ordering behavior . Paramagnetic resonance linewidth generation system There are two kinds of anisotropic interactions: the role of the crystal field (CF) and Dzyloshinsky-Moriya (DM) exchange interaction in electron paramagnetic resonance experiments . Below the charge ordering temperature TCO paramagnetic resonance linewidth increases with decreasing temperature , this phenomenon can be caused by narrowing of the movement mechanism (motional narrowing) Jahn-Teller polaron hopping to explain . Mossbauer spectroscopy experiments , we found that the lattice distortion of the system can detect Mossbauer spectrum technology and by Mossbauer spectroscopy technique , we can mixed valence Mn3 and Mn4 ion manganese oxide system separate.

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