On the Resistivity and Crystal Structure of Binary Oxide of Nickel and Cobalt

抄録

The solid solution MeO (Me=Ni₁Co₂) was prepared by quenching the specimens derived from mixture of nickel and cobalt carbonates from a temperature higher than 850°C. The resistivity measurement during the heat treatment provided a convenient measure of the phase change. MeO shows a high resistivity at room temperature and has a NaCl-type crystal structure with lattice parameter of 4.23₅ Å. We could lower its resistivity at our disposal through the definite heat treatment. The lowering of resistivity accompanied the shrinkage of lattice parameter and increase in oxygen content without appreciable change in crystal form. The conduction mechanism in MeO having low resistivity may be considered to be quite the same as in the case of black nickel oxide, except the degree of oxygen excess can amount to several percent in former case. The phase change in MeO, caused by the heat treatment was also investigated, in comparison with the case of pure cobalt and nickel oxides and the effect of mixing was discussed.