Coexistence of ferromagnetism and ferroelectricity in the van der Waals multiferroic CuIn0.2V0.8P2S6

TL;DR

This study reports a 2D van der Waals multiferroic material, CuIn0.2V0.8P2S6, that intrinsically exhibits both ferromagnetism at low temperature and room-temperature ferroelectricity, advancing multifunctional device potential.

Contribution

The paper demonstrates the realization of a single-phase 2D vdW multiferroic material with coexisting ferromagnetism and ferroelectricity, overcoming previous interface and stability limitations.

Findings

CuIn0.2V0.8P2S6 shows ferromagnetic ordering with TC of 14.6 K.

Ferroelectricity confirmed via ferroelectric tunnel junctions with high electroresistance.

Magnetodielectric response observed below TC, indicating interplay between orders.

Abstract

Two-dimensional (2D) van der Waals (vdW) multiferroics have emerged as a promising platform for next-generation multifunctional devices. Although recent studies have demonstrated that artificial heterostructures can combine dual ferroic orders and exhibit strong magnetoelectric coupling, their performance is sometimes limited by poor interface quality and inadequate long-term stability. By contrast, the realization of intrinsic single-phase materials with coexisting ferromagnetism and ferroelectricity remains a longstanding challenge in the field. Here we report the realization of a single-phase 2D vdW multiferroic system, CuIn0.2V0.8P2S6, which exhibits both ferromagnetism and room-temperature ferroelectricity. The intrinsic ferroelectric nature of CuIn0.2V0.8P2S6 was probed using ferroelectric tunnel junctions, which exhibit a large tunneling electroresistance with an ON/OFF ratio of 107 at 295 K. CuIn0.2V0.8P2S6 develops ferromagnetic ordering with the Curie temperature (TC) of 14.6 K, as evidenced by pronounced magnetic hysteresis and a relatively large remanent magnetization. Notably, the appearance of a magnetodielectric response below TC is consistent with the anticipated interplay between the ferromagnetic and ferroelectric orders. These results highlight a promising route toward single-phase van der Waals multiferroics with coexisting ferroic orders.