Uncommon magnetic ordering in the quantum magnet Yb$_{3}$Ga$_{5}$O$_{12}$

TL;DR

This study reveals an unusual antiferromagnetic order in Yb$_{3}$Ga$_{5}$O$_{12}$ at very low temperatures, highlighting complex magnetic interactions and quantum fluctuations in a frustrated garnet system.

Contribution

The paper identifies a novel magnetic propagation vector and structure in Yb$_{3}$Ga$_{5}$O$_{12}$, emphasizing the role of dipolar and exchange interactions in a nearly isotropic, frustrated magnet.

Findings

Unusual magnetic propagation vector ${\bf k}=(1/2, 1/2, 0)$ identified

Complex magnetic structure consistent with theoretical models

Reduced ordered moments suggest significant quantum fluctuations

Abstract

The antiferromagnetic structure of Yb$_{3}$Ga$_{5}$O$_{12}$ is identified by neutron diffraction experiments below the previously-known transition at $T_{\lambda}=54$ mK. The magnetic propagation vector is found to be ${\bf k}=(1/2, 1/2, 0)$, an unusual wave-vector in the garnet structure. The associated complex magnetic structure highlights the role of exchange interactions in a nearly isotropic system dominated by dipolar interactions and finds echos with exotic structures theoretically proposed. Reduced values of the ordered moments may indicate significant quantum fluctuations in this effective spin-1/2 geometrically frustrated magnet.