The insulating nature and the low intrinsic damping of rare earth iron garnets made them the material of choice for spintronic research. While yttrium iron garnet (YIG) thin films are well studied and especially known for their ultralow Gilbert damping parameter, recently other rare earth iron garnet (RIG) thin films with more complex magnetic structures have gained interest. Tunable magnetic properties like the magnetic compensation temperature or perpendicular magnetic anisotropy (PMA) are hereby of great interest for the implementation in spintronic devices. In this regard, calculations predict PMA which can be induced by magnetoelastic anisotropy for the RIGs, depending on the substrate choice and subsequent film strain. We have therefore investigated the influence of lattice mismatch provided by various garnet substrates and film stoichiometry on the structural and magnetic properties of gadolinium iron garnet (GdIG) thin films with thicknesses between 13 and 218 nm. Epitaxial, single-crystalline films exhibiting smooth interfaces were prepared by pulsed laser deposition at elevated temperatures. PMA is obtained for GdIG thin films grown under tensile in-plane strain on Gd3Sc2Ga3O12 (GSGG) substrates. Furthermore, a thickness series reveals a slow structural relaxation and PMA even for 218 nm thick GdIG films. In contrast, slightly off-stoichiometric films show a reduction or even loss in PMA. All GdIG films exhibit a magnetic compensation point in the range between 210–260 K, which is lower than for bulk (286 K). In addition, a temperature dependent spin reorientation transition was observed for GdIG/GSGG samples. Therefore, GdIG films provide tunable magnetic properties controllable by film strain, stoichiometry, and temperature, which will be beneficial for further research in the related fields of magnonics and spintronics.

Note: This paper is part of the Special Topic Collection on 30 years of the Nellie Yeoh Whetten Award -Celebrating the Women of the AVS.

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