Temperature dependence of the EPR spectra of KNiF 3

Abstract

The X-band EPR powder spectra of KNiF 3 has been measured from T N = 253 K to 530 K. A very broad asymmetric line was observed in all cases and, from a fitting procedure, the Larmor resonance fields H r and linewidths Δ H were obtained. While H r is constant and corresponds to g = 2.32 ± 0.04, the linewidth increases with temperature from 3.8 to 7.2 kOe. At temperature T > 1.4 T N, Δ H increases linearly with T suggesting that spin-lattice relaxation is dominated by one-phonon processes.