Weak ferromagnetism in magnetoelectrics LiCoPO4 and LiNiPO4

TL;DR

This study investigates the magnetic properties of LiCoPO4 and LiNiPO4 crystals, revealing weak ferromagnetism with different temperature behaviors and hysteresis characteristics, using SQUID magnetometry.

Contribution

It provides new insights into the weak ferromagnetic behavior and hysteresis properties of LiCoPO4 and LiNiPO4, which were not previously characterized in detail.

Findings

Both compounds exhibit weak ferromagnetism aligned along the antiferromagnetic axis.

LiCoPO4 shows non-monotonic temperature dependence of WFM moment.

LiCoPO4 displays a horizontal negative bias in magnetic hysteresis loops.

Abstract

The magnetic properties of the antiferromagnetic magnetoelectric single-crystals LiCoPO4 and LiNiPO4 were investigated using the SQUID-magnetometer. The magnetization was measured in a longitudinal experimental geometry (M // H) along the crystallographic axes a, b and c. The carried out investigations have shown that these compounds exhibit weak ferromagnetism. The weak ferromagnetic (WFM) moment is directed along the antiferromagnetic axis in both crystals. But the temperature behaviours of the weak ferromagnetic moments in LiCoPO4 and LiNiPO4 are different. The weak ferromagnetic moment in LiCoPO4 changes non-monotonically. The essential horizontal negative bias of the magnetic hysteresis loop is observed in LiCoPO4