Role of gallium diffusion in the formation of a magnetically dead layer at the Y3Fe5O12/Gd3Ga5O12 epitaxial interface

• Published in: Physical review materials 2018-10, Vol.2 (10)
• Main Authors: Suturin, S. M., Korovin, A. M., Bursian, V. E., Lutsev, L. , V, Bourobina, V, Yakovlev, N. L., Montecchi, M., Pasquali, L., Ukleev, V, Vorobiev, Alexei, Devishvili, A., Sokolov, N. S.
• Format: Article
• Language: English
• ISSN: 2475-9953
• DOI: 10.1103/PhysRevMaterials.2.104404

We have clarified the origin of a magnetically dead interface layer formed in yttrium iron garnet (YIG) films grown at above 700 degrees C onto a gadolinium gallium garnet (GGG) substrate by means of laser molecular beam epitaxy. The diffusion-assisted formation of a Ga-rich region at the YIG/GGG interface is demonstrated by means of composition depth profiling performed by x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and x-ray and neutron reflectometry. Our finding is in sharp contrast to the earlier expressed assumption that Gd acts as a migrant element in the YIG/GGG system. We further correlate the presence of a Ga-rich transition layer with considerable quenching of ferromagnetic resonance and spin wave propagation in thin YIG films. Finally, we clarify the origin of the enigmatic low-density overlayer that is often observed in neutron and x-ray reflectometry studies of the YIG/GGG epitaxial system.