| Summary: | 碩士 === 國立中山大學 === 物理學系研究所 === 104 === Geometrical spin frustrated system shows special and interesting physical properties. The energy of this system will be lowest in the ground state. Nevertheless, the spin ordering in some geometric lattices cannot stay in the particular direction in order to meet minimum energy in the ground state such as triangular lattice, Kagome lattice, Pyrochlore lattice and spinel structure.
Cu2OCl2 attracts much attention due to its pyrochlore lattice which has the corner-sharing tetrahedral and the geometrical frustration, leading to strong electron correlation amd quantum effect. The experimental results, including the magnetic properties and specific heat, confirmed that Cu2OCl2 is antiferromagnetism and has Néel temperature ~70K. Our research focused on the electrical properties of this material, and discussed the reasons of these phenomena.
Ferroelectric ordering is determined by using dielectric constant and electric polarization and the TC of the material ~75 K. The structural distortion observed by the temperature dependence of lattice constants (volume) is considered as the role to induce ferroelectricity. The mechanism of multiferroic in Cu2OCl2 might be related to the inverse DM interaction. Our findings must open a new candidate to attract more attention for the high TC multiferroic material.
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