Single-ion anisotropy in the gadolinium pyrochlores studied by an electron paramagnetic resonance

TL;DR

This study uses electron paramagnetic resonance to measure single-ion anisotropy in Gd3+ ions within pyrochlore structures, revealing strong easy-plane anisotropy and its implications for magnetic behavior.

Contribution

It provides the first detailed measurement of single-ion anisotropy in Gd-based pyrochlores using EPR, highlighting the significance of easy-plane anisotropy.

Findings

Gd3+ ions exhibit strong easy-plane anisotropy.

Anisotropy constant D is comparable to exchange integral J.

Easy-plane anisotropy influences magnetic phase transitions.

Abstract

The electron paramagnetic resonance is used to measure the single-ion anisotropy of Gd3+ ions in the pyrochlore structure of (Y{1-x}Gdx)2Ti2O7. A rather strong easy-plane type anisotropy is found. The anisotropy constant D is comparable to the exchange integral J in the prototype Gd2Ti2O7, D~0.75J and exceeds the dipolar energy scale. Physical implications of an easy-plane anisotropy for a pyrochlore antiferromagnet are considered. We calculate the magnetization curves at T=0 and discuss phase transitions in magnetic field.