钙钛矿型锰氧化物La1-x-yCaxKyMnO3系列样品的介电性质

应用水热氧化还原反应制备的La1-x-yCaxKyMnO3系列样品具有ABO3型钙钛矿结构，并且在A位同时拥有La3+，Ca2+和K+三种不同价态的阳离子。将La1-x-yCaxKyMnO3系列样品研磨压片，经烧结制成平行板电容器，在室温条件下，测试样品的电容、介电损耗和电阻随频率的变化。我们结合样品组成引起的A位离子失配度的变化，给出了La1-x-yCaxKyMnO3系列样品介电常数实部随A位离子变化的规律；对比样品电阻随频率变化的理论值和计算值说明样品内部属于电阻电容并联电路。

Dielectric Properties of a Series of Perovskite La1-x-yCaxKyMnO3 Manganites

A series of perovskite manganese oxides La1-x-yCaxKyMnO3 are synthesized from hydrothermal redox reaction, and they have La3+, Ca2+ and K+ three kinds of cations with different valences occupied at A site. The obtained samples are ground and pressed in discs, and the discs are then sintered to form a parallel-plate capacitor. At room temperature, the capacitance, the loss tangent and the resistance are measured as a function of frequency. We find that the real part of the complex relative dielectric permittivity varies considerably in different samples with the A-site cation size mismatch. The comparison of the resistance derived from experiment and calculation respectively indicates the equivalent circuit in intrinsic samples.