Temperature dependent epr measurements of Mn2+ in diamagnetic garnets

EPR measurements have been made of the spin Hamiltonian parameters of Mn²⁺ at the three different sites in each of the four diamagnetic garnets LuAlG, YAlG, LuGaG and YGaG. The temperature variation of all the second order crystal field parameters together with those of the fourth order crystal field parameter and the hyperfine splitting parameter for octahedral sites in YGaG have been followed over a range 4·2-550°K. The magnitude of the various parameters and their temperature variations are discussed.