Thickness-Dependent Magnetism Variation for Ferrimagnetic Rare-Earth/Transition Metal Fe1-xGdx Films

Published

August 13, 2025

Author(s)

Jenae Shoup, Julie Borchers, Timothy R. Charlton, Daniel Gopman, Alessandro Mazza, Dario A. Arena

Abstract

The magnetic compensation effect in rare earth: transition metal alloys, in which the magnetization of the antiferromagnetically-aligned rare earth and transition metal sublattices cancel each other out, can be utilized in a number of novel spintronic applications. However, nanoscale composition variations of the rare earth/transition metal ratio broaden the temperature range of magnetic compensation (i.e., near zero net magnetization) and can even result in the reversal of the dominant magnetic sublattice at a given temperature. We observe an unexpected spin-reorientation in sputter-grown Fe1-xGdx thin films with nominal x=0.28 as a function of film thickness. Thicker films (> 50 nm thickness) exhibit an in-plane anisotropy while robust out-of-plane anisotropy is observed in thin films (16 nm) at all temperatures. Correspondingly, the compensation temperature for thick films is near 25 K while that for thin films is above room temperature. A film with intermediate thickness (35 nm) displays a more complicated evolution of magnetic configurations. X-ray and polarized neutron scattering indicate that while structurally the intermediate thickness film appears homogeneous along the film normal direction, its depth-dependent magnetization profile is unusual with two phases that have different compensation behavior. Elemental mapping using high-resolution electron microscopy reveals column formation leading to lateral variations in the Fe:Gd ratio near the top of the film while Fe and Gd are uniformly distributed near the bottom of the layer. Our results identify a transitional thickness region in Fe1-xGdx films where the non-uniform elemental distribution leads to complex multi-step magnetization behavior that should be controlled or could be leveraged in spintronic and magneto-optical applications.

Citation

Physical Review Materials

Volume

9

Issue

8

Pub Type

Journals

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DOI Link

Keywords

Compensation temperature, polarized neutron reflectivity, magnetic film

Citation

Shoup, J. , Borchers, J. , Charlton, T. , Gopman, D. , Mazza, A. and Arena, D. (2025), Thickness-Dependent Magnetism Variation for Ferrimagnetic Rare-Earth/Transition Metal Fe1-xGdx Films, Physical Review Materials, [online], https://doi.org/ 10.1103/18l1-7lcw (Accessed October 14, 2025)