Electron Spin Resonance of Gd3+in Lanthanum Fluoride

Abstract

Electron spin resonance in a single crystal of LaF₃ containing 0.01% Gd³⁺ shows three magnetically distinguishable ions per unit cell in a rhombic crystalline electric field which is consistent with a hexamolecular unit cell of symmetry C6/mcm. This is in disagreement with recent crystallographic measurements, but in agreement with the interpretation of the Faraday rotation given by Van Vleck and Hebb. The parameters of the spin Hamiltonian are given in table 1. The crystal field splitting in zero magnetic field is of the order of 0.3 cm^-1 which makes this a possible salt for maser operation in low magnetic field.