Magnetic-field induced melting of long-range magnetic order akin to Kitaev insulators in the metallic compound Tb5Si3

TL;DR

This study demonstrates that a metallic compound, Tb5Si3, exhibits magnetic-field-induced melting of long-range magnetic order, akin to Kitaev insulators, revealing novel high-field magnetic disorder behavior in a heavy rare-earth system.

Contribution

It shows that Tb5Si3, a metallic compound with a honeycomb magnetic network, exhibits field-induced suppression of magnetic order similar to Kitaev physics, a behavior not previously reported in such systems.

Findings

Magnetic order in Tb5Si3 is suppressed by a critical magnetic field.

Neutron diffraction reveals incommensurate magnetic structures beyond the critical field.

Magnetic entropy peaks indicate magnetic disorder in a narrow field range.

Abstract

There have been constant efforts to find exotic quantum spin-liquid (QSL) materials. Some of the transition metal insulators dominated by the direction dependent anisotropic exchange interaction (Kitaev model for honeycomb network of magnetic ions) are considered to be promising cases for the same. In such Kitaev insulators, QSL is achieved from the zero-field antiferromagnetic state by the application of magnetic field, suppressing other exchange interactions responsible for magnetic order. Here, we show that the features attributable to long-range magnetic ordering of the intermetallic compound, Tb5Si3 (T_N= 69 K), containing honey-comb network of Tb ions, are completely suppressed by a critical applied field, H_cr, in heat-capacity and magnetization data, mimicking the behavior of Kitaev physics candidates. The neutron diffraction patterns as a function of H reveal that it is an incommensurate magnetic structure that gets suppressed, showing peaks arising from multiple wave vectors beyond Hcr. Increasing magnetic entropy as a function of H with a peak in the magnetically ordered state is in support of some kind of magnetic disorder in a narrow field range after H_cr. Such a high-field behavior for a metallic heavy rare-earth system to our knowledge has not been reported in the past and therefore is intriguing.