Electron paramagnetic resonance study of gadolinium–gallium–garnet

Abstract

The electron paramagnetic resonance (EPR) in a single crystal of gadolinium–gallium–garnet has been studied with the aim of understanding the behavior of EPR in systems with large dipolar and small exchange fields, such as encountered in many of the rare-earth based high Tc superconducting compounds. Only one wide line, arising from Gd3+ has been observed. Its shape at room temperature is analyzed using the Kubo–Toyabe [Magnetic Resonance and Relaxation, edited by R. Blinc (North Holland, Amsterdam, 1967), p. 810] stochastic model for the line shape at static modulation. At low T, the anisotropy in the resonance field is a purely shape effect.