Proximity-induced interfacial room-temperature ferromagnetism in semiconducting Fe3GeTe2

TL;DR

This study demonstrates that magnetic proximity effects at the interface between Pt and semiconducting Fe3GeTe2 can induce ferromagnetism above room temperature, enabling potential spintronic applications without additional magnetic doping.

Contribution

It reveals that Pt can induce room-temperature ferromagnetism in Fe3GeTe2 through proximity effects, offering a new method to achieve high-temperature ferromagnetism in 2D materials.

Findings

Room-temperature ferromagnetism induced at Fe3GeTe2/Pt interfaces

Spin current at interfaces is more than doubled

Proximity effect confirmed as the origin of ferromagnetism

Abstract

The discoveries of two-dimensional ferromagnetism and magnetic semiconductors highly enrich the magnetic material family for constructing spin-based electronic devices but with an acknowledged challenge that the Curie temperature (Tc) is usually far below room temperature. Many efforts such as voltage control and magnetic ion doping are currently underway to enhance the functional temperature, in which the involvement of additional electrodes or extra magnetic ions limits their plenty of applications in practical devices. Here we demonstrate that the magnetic proximity, a robust effect but with elusive mechanisms, can induce room-temperature ferromagnetism at the interface between sputtered Pt and semiconducting Fe3GeTe2, both of which do not show ferromagnetism at 300 K. The independent electrical and magnetization measurements, structure analysis, and control samples with Ta highlighting the role of Pt confirm that the ferromagnetism with the Tc of above 400 K arises from the Fe3GeTe2/Pt interfaces, rather than Fe aggregation or other artificial effects. Moreover, contrary to conventional ferromagnet/Pt structures, the spin current generated by the Pt layer is enhanced more than two times at the Fe3GeTe2/Pt interfaces, indicating the potential applications of the unique proximity effect in building high-efficient spintronic devices. These results may pave a new avenue to create room-temperature functional spin devices based on low-Tc materials and provide clear evidences of magnetic proximity effects by using non-ferromagnetic materials.