Jahn-Teller effect in low-spin Ni3+ in the LaAlO3 ceramic

This paper reports on an EPR study of LaAl1 - xNixO3 solid solutions with x less than or equal to 0.12 made in the 4.2- to 300-K temperature range. In the X range, the broadening of the single EPR line with g(eff) = 2.148 was observed at temperatures below similar to40 K. In the Q range, a slightly anisotropic EPR line with g(perpendicular to)(') = 2.145 +/- 0.002 and g(parallel to)(') = 2.154 +/- 0.002 transforms to a rhombic-symmetry spectrum with g(1) = 2.183 +/- 0.002, g(2) = 2.143 +/- 0.002, and g(3) = 2.118 +/- 0.002. It is shown that the observed low-temperature effects are due to the lowered symmetry of the complex under the combined action of the tetragonal Jahn-Teller distortions and of the trigonal component of the crystal field. (C) 2002 MAIK "Nauka / Interperiodica".