Nonreciprocal transport in a Rashba ferromagnet, delafossite PdCoO${}_2$

Abstract

Rashba interfaces yield efficient spin-charge interconversion and give rise to nonreciprocal transport phenomena. Here, we report magnetotransport experiments in few-nanometer-thick films of PdCoO${}_2$, a delafossite oxide known to display a large Rashba splitting and surface ferromagnetism. By analyzing the angle dependence of the first- and second-harmonic longitudinal and transverse resistivities, we identify a Rashba-driven unidirectional magnetoresistance that competes with the anomalous Nernst effect below the Curie point. We estimate a Rashba coefficient of 0.75 {\pm} 0.3 eV Å and argue that our results qualify delafossites as a new family of oxides for nano-spintronics and spin-orbitronics, beyond perovskite materials.

Accepted in Nano Lett

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