Inducing ferromagnetism and Kondo effect in platinum by paramagnetic ionic gating

TL;DR

This paper demonstrates reversible electrical control of ferromagnetism and Kondo effect in platinum using paramagnetic ionic liquid gating, enabling new possibilities for spintronic devices with tunable magnetic and transport properties.

Contribution

It introduces a novel ionic gating method to induce and control ferromagnetism and Kondo effect in platinum, combining field-effect and magnetic phenomena at the interface.

Findings

Reversible switching of ferromagnetic states in platinum films.

Observation of Kondo effect at low temperatures.

Induction of perpendicular anisotropy and large coercivity.

Abstract

Electrically controllable magnetism, which requires the field-effect manipulation of both charge and spin degrees of freedom, has attracted growing interests since the emergence of spintronics. In this work, we report the reversible electrical switching of ferromagnetic (FM) states in platinum (Pt) thin films by introducing paramagnetic ionic liquid (PIL) as the gating media. The paramagnetic ionic gating controls the movement of ions with magnetic moments, which induces itinerant ferromagnetism on the surface of Pt films with large coercivity and perpendicular anisotropy mimicking the ideal two-dimensional Ising-type FM state. The electrical transport of the induced FM state shows Kondo effect at low temperature suggesting spatially separated coexistence of Kondo scattering beneath the FM interface. The tunable FM state indicates that paramagnetic ionic gating could serve as a versatile method to induce rich transport phenomena combining field effect and magnetism at PIL-gated interfaces.