Impedance spectroscopy is performed to establish the electrical property and microstructure relations of the asdeposited and post-annealed polycrystalline CaCu3Ti4O12 （CCTO） films. Our results show that the resistan...Impedance spectroscopy is performed to establish the electrical property and microstructure relations of the asdeposited and post-annealed polycrystalline CaCu3Ti4O12 （CCTO） films. Our results show that the resistance and capacitance of the grains and grain boundaries could be tuned by changing the annealing atmosphere and temperature. The simple resistor-capacitor equivalent circuit and the modified constant phase element （CPE） circuit are used to describe the impedance spectroscopy, and excellent agreement between the calculated and measured curves is obtained in the CPE circuit. Based on the experimental results, it is suggested that the origin of the semiconductivity of the grains in CCTO polycrystalline films originates from their oxygen-loss, while the grain boundaries are close to oxygen- stoichiometry.展开更多
采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4...采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4O12多晶块具有巨介电常数,混合价Ti离子导致极化子的热激活使Ca Cu3Ti4O12多晶块的介电特性出现反常效应。展开更多
基金Supported by the National Natural Science Foundation of China Grant No 10204016.
文摘Impedance spectroscopy is performed to establish the electrical property and microstructure relations of the asdeposited and post-annealed polycrystalline CaCu3Ti4O12 （CCTO） films. Our results show that the resistance and capacitance of the grains and grain boundaries could be tuned by changing the annealing atmosphere and temperature. The simple resistor-capacitor equivalent circuit and the modified constant phase element （CPE） circuit are used to describe the impedance spectroscopy, and excellent agreement between the calculated and measured curves is obtained in the CPE circuit. Based on the experimental results, it is suggested that the origin of the semiconductivity of the grains in CCTO polycrystalline films originates from their oxygen-loss, while the grain boundaries are close to oxygen- stoichiometry.
文摘采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4O12多晶块具有巨介电常数,混合价Ti离子导致极化子的热激活使Ca Cu3Ti4O12多晶块的介电特性出现反常效应。
