Interfacial Magnetic Characteristics of Nearly Compensated Gadolinium Iron Garnet

Published

May 4, 2024

Author(s)

Karthik Srinivasan, Alexander Grutter, Thomas Gage, P. Quarterman, Christy Kinane, Andrew Caruana, Guichuan Yu, Javier Garcia-Barriocanal, Sean Langridge, Bethanie Stadler

Abstract

Reports on spin Hall magnetoresistance, magnonic spin currents from thermal gradients, and spin transfertorque magnetic random-access memory using compensated ferrimagnets largely discuss bulk magnetization but lack consideration of depth profiles or interfacial characteristics. Here, magnetic and structural characterization of profiles and interfaces was performed for nearly compensated gadolinium iron garnet (GdIG) thin films. X-ray diffraction and reciprocal space maps show that sputter deposited GdIG on Si is polycrystalline with the desired cubic garnet phase, and GdIG on gadolinium gallium garnet (GGG) is epitaxial with <0.06% compressive strain. Temperature-dependent magnetometry confirms the compensation temperatures of GGG/GdIG and Si/GdIG to be 285 and 260 K, respectively, both near room temperature. Interestingly, these measurements suggest the presence of unsaturated rare-earth moments, which result in a characteristic hysteresis between heating and cooling sequences in the magnetization temperature curves at zero field. Depth-profile measurements from polarized neutron reflectometry (PNR) indicate up to 91% volume fraction in GdIG on Si. At the interface, PNR reveals a region containing magnetized Fe-doped GGG, a low-density GdIG at the GGG/GdIG interface, and a thin magnetically dead layer at the Si/GdIG interface. Cross-sectional transmission electron microscopy and energy dispersive x-ray spectroscopy confirm the assessment of PNR. The magnetic characteristics of interfacial regions are attributed to intermixing of Fe-Ga at the GGG/GdIG interface and the presence of amorphous Fe-Si at the Si/GdIG interface.

Citation

Physical Review Materials

Volume

8

Issue

4

Pub Type

Journals

Download Paper

https://doi.org/10.1103/PhysRevMaterials.8.044403

Local Download

Keywords

Garnet, Sputtering, Magnetism, Thin Film

Citation

Srinivasan, K. , Grutter, A. , Gage, T. , Quarterman, P. , Kinane, C. , Caruana, A. , Yu, G. , Garcia-Barriocanal, J. , Langridge, S. and Stadler, B. (2024), Interfacial Magnetic Characteristics of Nearly Compensated Gadolinium Iron Garnet, Physical Review Materials, [online], https://doi.org/10.1103/PhysRevMaterials.8.044403, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936586 (Accessed December 11, 2024)