巨介电常数材料CCTO的可变程跳跃电导研究

摘要

The ac conductivity and dielectric properties of CaCu3Ti4O12 (CCTO) ceramics were investigated in a temperature range of-120℃to 300℃and a frequency range of 1 Hz to 10 MHz. Two different conduction processes, which can be well described by Mott’s variable-range-hopping (VRH) mechanism, were observed in different temperature regions. The high temperature VRH conduction is related to the second ionization of oxygen vacancy. The low temperature dielectric properties of CCTO could be described by the so-called universal dielectric response (UDR) when a polaron relaxation is considered.%文章研究了巨介电常数材料CaCu3Ti4O12(CCTO)在宽温区(－120℃～300℃)及宽频域(1 Hz～10 MHz)的交流电导及介电性能。在低温区和高温区，CCTO表现出两种不同的导电过程，均可以由Mott提出的可变程跳跃电导机制(Variable-Range-Hopping，VRH)来描述。研究发现高温VRH过程与氧空位的二次离子化相关，而低温过程符合普适介电响应方程，其介电弛豫行为起源于极化子的弛豫。