Ni-defective value and resistivity of sputtered NiO films

The lattice constant of the rhombohedral NiO films is larger than that of the bulk and depends on the O-2 partial pressure (P-O) during the reactive sputtering; the axis angle is close to that of the bulk. The anisotropy of magnetic susceptibility chi is observed, and the average value (1.2 x 10(-9) H/m) is the same as that of the bulk. Rutherford back scattering (RBS) analysis shows that the NiO films are confirmed to be non-stoichiometric and the Ni-defective value gamma in Ni1-gammaO films is 0.14-0.23; gamma increases with P-O. The electric resistivity rho (similar to1 Ohm cm.) of the NiO film is four orders of magnitude smaller than that of bulk NiO, and decreases slightly with increasing gamma. (C) 2001 Elsevier Science B.V. All rights reserved.