Effective reduction of PdCoO2 thin films via hydrogenation and sign tunable anomalous Hall effect

TL;DR

This paper demonstrates that mild hydrogenation of PdCoO2 thin films induces ferromagnetism and a tunable anomalous Hall effect, opening new avenues for spintronic applications with oxide materials.

Contribution

It introduces a novel hydrogenation process that transforms PdCoO2 into a ferromagnetic alloy with tunable electronic properties, a significant advancement over previous nonmagnetic oxide films.

Findings

Hydrogenation induces ferromagnetism in PdCoO2.

Hydrogenation enables sign-tunable anomalous Hall effect.

Potential for creating novel spintronic heterostructures.

Abstract

PdCoO2 , belonging to a family of triangular oxides called delafossite, is one of the most conducting oxides. Its in-plane conductivity is comparable to those of the best metals, and exhibits hydrodynamic electronic transport with extremely long mean free path at cryogenic temperatures. Nonetheless, it is nonmagnetic despite the presence of the cobalt ion. Here, we show that a mild hydrogenation process reduces PdCoO2 thin films to an atomically-mixed alloy of PdCo with strong out-of-plane ferromagnetism and sign-tunable anomalous Hall effect. Considering that many other compounds remain little affected under a similar hydrogenation condition, this discovery may provide a route to creating novel spintronic heterostructures combining strong ferromagnetism, involving oxides and other functional materials.