EPR Pressure Experiments on Rare Earths in Diamagnetic Garnets and the Single-Ion Magnetostriction of Rare-Earth Iron Garnets

Abstract

The EPR spectra of Gd³⁺, Yb³⁺, and Er³⁺ in diamagnetic garnet hosts have been measured as uniaxial pressures were applied to the crystal, and the parameters ∂g_kl/∂ε_ij and ∂D_kl/∂ε_ij evaluated. A theory connecting these parameters with the magnetoelastic energy of the rare‐earth iron garnets has been developed, and the single‐ion contribution to the magnetostriction constants λ₁₀₀ and λ₁₁₁ of GdIG, YbIG, and ErIG calculated. In most cases the predicted single‐ion magnetostriction constants are of the same sign and within a factor of 2 of the observed magnetostriction constants at low temperatures. We conclude that single‐ion effects play a dominant role in the magnetoelastic behavior of the rare‐earth iron garnets.