Optical measurements in single crystal ErCrO3

The optical⁴ I _15/2→⁴ S _3/2 transition of Er³⁺ in single crystal ErCrO₃ has been studied with polarized light as a function of temperature between 1.7 and 140 °K and of applied magnetic fields in the temperature region between 1.7 and 10 °K. The temperature dependence of the ground state splitting has been deduced from these measurements. ErCrO₃ undergoes a spin reorientation with a reorientation temperature depending on applied external field. The reorientation temperature in zero field was determined to beT _r =9.4±0.5 °K. The experiments in external magnetic field along thez-axis have given the magnetic moment of the Er³⁺ ions to be μ _z =5.55 (±0.45) μ _b and the reorientation fieldH _z ^r as a function of temperature. Specific heat and magnetization data have been calculated from the optical data of the Er³⁺ ground state and compared with recent specific heat and magnetization studies in ErCrO₃ by other authors.