Application of the superposition model of the crystal field to rare-earth garnets

The superposition model (SM) analysis of the crystal field parameters (CFP) in 14 Nd3+, Eu3+, Tb3+, Dy3+ and Er3+ garnets is presented. The ratio of the average values of exponents defining the radial dependence of the intrinsic parameters in these garnets is t6/t4≲0.5 in contrast to the results of Newman and Stedman, who obtained t6/t4≳1 in their earlier study of rare earth garnets. The possibility of using the SM for the quantitative prediction of the CFP’s by extrapolation from one garnet structure to another is demonstrated on Tb3+. Starting with the CFP’s reported for TbAG we extrapolate them to TbIG. From the CFP’s obtained in this way the CF effect on magnetization is calculated and compared with the high field measurements.