Sputtered terbium iron garnet films with perpendicular magnetic anisotropy for spintronic applications

TL;DR

This paper demonstrates the successful fabrication of epitaxial terbium iron garnet ultrathin films with large perpendicular magnetic anisotropy via magnetron sputtering, highlighting their tunable properties and potential for spintronic applications.

Contribution

It introduces a sputtering method to produce high-quality TbIG films with controllable magnetic properties suitable for spintronics.

Findings

Achieved high crystallinity in sputtered TbIG films.

Demonstrated large perpendicular magnetic anisotropy (PMA).

Identified the ferrimagnetic compensation temperature range.

Abstract

We report the structural, magnetic, and interfacial spin transport properties of epitaxial terbium iron garnet (TbIG) ultrathin films deposited by magnetron sputtering. High crystallinity was achieved by growing the films on gadolinium gallium garnet (GGG) substrates either at high temperature, or at room temperature followed by thermal annealing, above 750 {\deg}C in both cases. The films display large perpendicular magnetic anisotropy (PMA) induced by compressive strain, and tunable structural and magnetic properties through growth conditions or the substrate lattice parameter choice. The ferrimagnetic compensation temperature (TM) of selected TbIG films was measured through temperature-dependent anomalous Hall effect (AHE) in Pt/TbIG heterostructures. In the studied films, TM was found to be between 190-225 K, i.e., approximately 25-60 K lower than the bulk value, which is attributed to the combined action of Tb deficiency and oxygen vacancies in the garnet lattice evidenced by x-ray photoelectron spectroscopy measurements. Sputtered TbIG ultrathin films with large PMA and highly tunable properties reported here can provide a suitable material platform for a wide range of spintronic experiments and device applications.