Spin-glass transition in bond-disordered Heisenberg antiferromagnets coupled with local lattice distortions on a pyrochlore lattice

TL;DR

This study uses Monte Carlo simulations to show that coupling to local lattice distortions significantly enhances the spin-glass transition temperature in bond-disordered Heisenberg antiferromagnets on a pyrochlore lattice, with transition properties similar to canonical spin glasses.

Contribution

It reveals how spin-lattice coupling modifies the spin-glass transition, making it largely independent of disorder strength and similar to canonical models.

Findings

Spin-glass transition temperature is greatly increased by spin-lattice coupling.

Transition properties match those of canonical Heisenberg spin glasses.

Transition temperature becomes almost independent of disorder strength.

Abstract

Motivated by puzzling characteristics of spin-glass transitions widely observed in pyrochlore-based frustrated materials, we investigate effects of coupling to local lattice distortions in a bond-disordered antiferromagnet on the pyrochlore lattice by extensive Monte Carlo simulations. We show that the spin-glass transition temperature $\TSG$ is largely enhanced by the spin-lattice coupling, and furthermore, becomes almost independent of $\Delta$ in a wide range of the disorder strength $\Delta$. The critical property of the spin glass transition is indistinguishable from that of the canonical Heisenberg spin glass in the entire range of $\Delta$. These peculiar behaviors are ascribed to a modification of the degenerate manifold from continuous to semidiscrete one by the spin-lattice coupling.