Chemical solution synthesis and ferromagnetic resonance of epitaxial thin films of yttrium iron garnet

We report the fabrication of epitaxial Y3Fe5O12 (YIG) thin films on Gd3Ga5O12 (111) using a chemical solution method. Cubic YIG is a ferrimagnetic material at room temperature, with excellent magneto-optical properties, high electrical resistivity, and a very narrow ferromagnetic resonance, which makes it particularly suitable for applications in filters and resonators at microwave frequencies. But these properties depend on the precise stoichiometry and distribution of Fe3+ ions among the octahedral/tetrahedral sites of a complex structure, which hampered the production of high-quality YIG thin films by affordable chemical methods. Here we report the chemical solution synthesis of YIG thin films, with excellent chemical, crystalline, and magnetic homogeneity. The films show a very narrow ferromagnetic resonance (long spin relaxation time), comparable to that obtained from high-vacuum physical deposition methods. These results demonstrate that chemical methods can compete to develop nanometer-thick YIG films with the quality required for spintronic devices and other high-frequency applications.
This work was supported by the Ministry of Science of Spain (Projects No. MAT2016-80762-R, MAT2017-82970-C2-R, and No. MAT2014-51982-C2), the Consellería de Cultura, Educación e Ordenación Universitaria, Xunta de Galicia (ED431F 2016/008, and Centro Singular de Investigación de Galicia Accreditation 2016–2019, ED431G/09), the European Regional Development Fund (ERDF), and the Aragón Regional Government through Projects E26. The microscopy works have been conducted in the Laboratorio de Microscopías Avanzadas (LMA) at Instituto de Nanociencia de Aragón (INA), Universidad de Zaragoza. The authors acknowledge the LMA-INA for offering access to their instruments and expertise. Pilar Jiménez-Cavero acknowledges Spanish MECD for support through FPU program (Reference No. FPU014/02546).