Structural distortion induced enhancement of magnetic and dielectric properties in Pr modified yttrium iron garnet films

Low saturation magnetization and low dielectric constant significantly limited the application of Yttrium iron garnet (Y3Fe5O12, YIG) film, which could be enhanced through structural distortion. In this work, Y3-xPrxFe5O12 (YPrxIG) films were fabricated using chemical solution deposition method. The substitution of Pr3+ for Y3+ was adopted to regulate the symmetry of its polyhedron to induce a structural distortion owing to a larger ion radius of Pr3+ than that of Y3+. YPr0.20IG film exhibited a higher saturation magnetization of 241.2 emu/cm3 than the pure YIG film owing to the enhanced super-exchange from the increased FeO-O-FeT bond angle. The dielectric constant of YPr0.20IG film increased to 22.4 at 12.4 GHz, which was the contribution of electron polarization and ion polarization of Fe2+. The band gap value of YPr0.20IG film was reduced to 2.80 eV. These could be physically clarified that the electrons between Fe2+ and Fe3+ turned to migrate from the valence band to the conduction band.