材料期刊网

By using the optical spectral parameters of (NiF6)3- clusters in KMgF3:Ni3+ and CsCaF3:Ni3+ crystals estimated from the observed values in pure K3NiF6 crystal, the electron paramagnetic resonance (EPR) g factors for KMgF3:Ni3+ and CsCaF3:Ni3+ are calculated from the second-order perturbation formula (with the high-spin ground orbital state) based on the cluster approach. The results are in reasonable agreement with the observed values. The spin transition from the low-spin state in pure K3NiF6 crystal to the high-spin state in KMgF3:Ni3+ and CsCaF3:Ni3+ crystals owing to the slight increase of Ni3+ - F- distance is discussed.