CaCu3Ti4O12和La2/3Cu3Ti4O12陶瓷的电导特性

采用固相反应法制备CaCu₃Ti₄O₁₂和La_2/3Cu₃Ti₄O₁₂陶瓷材料并研究了其电导特性.结果表明，CaCu₃Ti₄O₁₂和La_2/3Cu₃Ti₄O₁₂的电导率随温度的变化规律相似.在低温（<150 K ) 区域，CaCu₃Ti₄O₁₂的电导率随温度升高而增大，即呈负阻温特性；在150~170 K温度区域，电导率出现极大值，且其电导率极大值为La_2/3Cu₃Ti₄O₁₂的近4倍；在较高的温度（170~250 K ）区域，电导率随温度的升高而减小.这是由于Ca2＋被La3＋替代后在该位置留下1/3空位而使La_2/3Cu₃Ti₄O₁₂的激活能高达1.01 eV 的缘故.

Conductance of Like Perovskite Structure ACu3Ti4O12 Materials

CaCu₃Ti₄O₁₂ and La2/3Cu3Ti4O12 materials were prepared by solid reaction process, and the conductance properties were measured and studied. The experimental data show that the conductance temperature curves of CaCu₃Ti₄O₁₂ and La_2/3Cu₃Ti₄O₁₂ are similar. In the lower temperature range (<150 K), the conductance increases with the temperature and the samples exhibit negative resistance temperature properties. In the temperature range of 150－170 K, the conductance reaches its maximum. Then, in the higher temperature range (170－250 K), the conductance decreases with the temperature. But the maximum value of conductance of CaCu₃Ti₄O₁₂ is about 3 times larger than that of La_2/3Cu₃Ti₄O₁₂. Further analysis shows that after Ca ^_2＋ is replaced by La ^_3＋, one third of vacancies remain in A sites, which results in the activation energy of La_2/3Cu₃Ti₄O₁₂ reaching 1.01 eV. The higher activation energy is the main cause of lower conductance of La_2/3Cu₃Ti₄O₁₂.