Platinum/Yttrium Iron Garnet Inverted Structures for Spin Current Transport

TL;DR

This paper demonstrates the growth of high-quality, single-crystal YIG films on GGG substrates with atomically sharp interfaces, enabling efficient spin current transport in inverted Pt/YIG structures.

Contribution

It reports a novel method for growing epitaxial YIG films on GGG with atomically sharp interfaces and excellent magnetic and spin transport properties.

Findings

YIG films are 30-80 nm thick and grown by pulsed laser deposition.

Post-growth annealing yields single-crystal YIG(110) with atomic surface steps.

Spin Hall magnetoresistance and spin Seebeck effects indicate high interface quality.

Abstract

30-80 nm thick yttrium iron garnet (YIG) films are grown by pulsed laser deposition on a 5 nm thick sputtered Pt atop gadolinium gallium garnet substrate (GGG) (110). Upon post-growth rapid thermal annealing, single crystal YIG(110) emerges as if it were epitaxially grown on GGG(110) despite the presence of the intermediate Pt film. The YIG surface shows atomic steps with the root-mean-square roughness of 0.12 nm on flat terraces. Both Pt/YIG and GGG/Pt interfaces are atomically sharp. The resulting YIG(110) films show clear in-plane uniaxial magnetic anisotropy with a well-defined easy axis along <001> and a peak-to-peak ferromagnetic resonance linewidth of 7.5 Oe at 9.32 GHz, similar to YIG epitaxilly grown on GGG. Both spin Hall magnetoresistance and longitudinal spin Seebeck effects in the inverted bilayers indicate excellent Pt/YIG interface quality.