Magnetic Phase Diagrams with Possible Field-induced Antiferroquadrupolar Order in TbB$_2$C$_2$

TL;DR

This study clarifies the magnetic phase diagrams of TbB₂C₂, revealing field-induced antiferroquadrupolar order and anomalous Néel temperature enhancement under magnetic fields, with implications for understanding AFQ and AFM interactions.

Contribution

It provides the first detailed phase diagrams of TbB₂C₂ showing field-induced AFQ phases and explains the magnetic behavior through competition between AFQ and AFM interactions.

Findings

Néel temperature is enhanced by magnetic fields, reaching 13.5 K at 10 T for <1 1 0> direction.

Magnetization and phase diagrams are explained by field-induced antiferroquadrupolar phases.

Systematic understanding of AFQ compounds in RB₂C₂ based on AFQ and AFM interactions.

Abstract

Magnetic phase diagrams of a tetragonal antiferromagnet TbB$_2$C$_2$ were clarified by temperature and field dependence of magnetization. It is noticeable that the N{\'e}el temperature in TbB$_2$C$_2$ is anomalously enhanced with magnetic fields, in particular the enhancement reaches 13.5 K for the ${<}1 1 0{>}$ direction at 10 T. The magnetization processes as well as the phase diagrams are well interpreted assuming that there appear field-induced antiferroquadrupolar ordered phases in TbB$_2$C$_2$. The phase diagrams of the AFQ compounds in RB$_2$C$_2$ are systematically understood in terms of the competition with AFQ and AFM interactions.