High-field magnetoelectric coupling and successive magnetic transitions in Mn-doped polar antiferromagnet Ni3TeO6

TL;DR

This study investigates the complex magnetic and magnetoelectric behaviors of Mn-doped Ni3TeO6, revealing multiple magnetic transitions, metamagnetic phenomena, and different orders of ME coupling, advancing understanding of magnetoelectric mechanisms in this class of materials.

Contribution

The paper provides the first detailed high-field analysis of Mn-doped Ni3TeO6, uncovering new magnetic phases and elucidating the nature of ME coupling mechanisms in this compound.

Findings

Discovery of weak ferromagnetism below 9.5 K in Mn-doped Ni3TeO6.

Observation of two distinct metamagnetic transitions at high magnetic fields.

Identification of temperature-dependent first- and second-order magnetoelectric effects.

Abstract

Among the 3d transition metal ions doped polar Ni3TeO6, Mn-doped Ni3TeO6 has stimulated great interest due to its high magnetic ordering temperature and complex magnetic phases, but the mechanism of magnetoelectric (ME) coupling is far from understood. Herein we report our systematic investigation of the chemical control of magnetism, metamagnetic transition, and ME properties of Ni3-xMnxTeO6 single crystals in high magnetic field (H) up to 52 T. We present a previously unreported weak ferromagnetic behavior appeared in the ab plane below 9.5 K in addition to the incommensurate helical and commensurate collinear antiferromagnetic states. In the low-field region, a spin-flop type metamagnetic transition without any hysteresis occurs at Hc1 for H // c, while another metamagnetic transition accompanied with a change in electric polarization is observed at Hc2 in the high-field region both for H // c and H // ab above 30 K, which can be attributed to the sudden rotation of magnetic moments at Ni2 sites. The ME measurements reveal that a first-order ME effect is observed in the low-T and low-H regions, while a second-order ME coupling term appears above 30 K in the magnetic field range of Hc1 < H < Hc2 for H // c and H < Hc2 for H // ab, both becoming significant with increasing temperature. Eventually, they are dominated by the second-order ME effect near the antiferromagnetic transition temperature. The present work demonstrates that Ni3-xMnxTeO6 is an exotic magnetoelectric material compared with Ni3TeO6 and its derivatives, thereby providing insights to better understand the magnetism and ME coupling in Ni3TeO6 and its derivatives.