Electrical Properties of Li_xNi_<(1-x)> O Single Crystals

概要

論文の詳細を見る
Aiming at a better understanding of still vague conduction processes in NiO, extensive measurements of the electrical resistivity ρ were made between 300 and 1020°K on Li_xNi_<(1-x)>O single crystals epitaxially grown on the MgO substrates, where x from zero up to 0.065 was controlled by diffusion method. The main results are as follows: (1) Iog ρ(/T) vs 1/T forms two straight lines, folded at a transition temperature T^*. Each T^* is close to the Neel temperature of NiO but a slight decreasing function of x. (2) With increasing x two activation energies ε_1(T>T^*) and ε_t(T<T^*), their difference ε_2-ε_l, and ρ sharply decrease at first (3) When x increases above 0.015, ε_1 approaches a final constant of 0.14eV, and ε_2-ε_1 to kT^* with a maximum error of 20%, while ρ still exhibits a gentle decrease. (4) ε_2-ε_1 always has the positive sign which is opposite to that of early sintered samples. These results are discussed in terms of Toyozawa's hopping model. The initial rapid decrease in ε_1,ε_2, and ρ with increasing x is explained by the sharp decrease in the attracting potential of neighboring Li+ion, and the saturation value of the activation energy corresponds to the activation energy for the hopping process.
社団法人日本物理学会の論文
1965-01-05