Orientational Switching\nof Perpendicular Magnetic\nAnisotropy and Near-Infrared Plasmonic States in SrRuO<sub>3</sub> Thin Films: Implications for Spintronic Devices

The precise manipulation of perpendicular\nmagnetic anisotropy\n(PMA)\nand near-infrared plasmonic states holds immense significance for\nadvanced nanoscale spintronics devices including magnetic random-access\nmemory and epsilon-near-zero (ENZ) photonic devices. Notwithstanding\nthe inherent tendency of oxide thin films to favor an in-plane magnetic\neasy axis, our study unveils an innovative approach to exert experimental\ncontrol over magnetic anisotropy, magnetic phase in SrRuO<sub>3</sub> (SRO) films by growing them coherently and controlling at nanoscale\nlevels via reflection high-energy electron diffraction (RHEED)-assisted\npulsed laser deposition (PLD) on distinctively orientedspecifically,\n(001), (011), and (111) SrTiO<sub>3</sub> (STO) single crystalline\nsubstrates. Our comprehensive magnetic measurements unequivocally\nconfirm a clear dependence on magnetic anisotropy with more than one\ncompeting magnetic phase with different coercivity and saturation\nmagnetization. A larger perpendicular magnetic anisotropy (PMA) is\nobserved for coherently strained SRO films on (001)-oriented STO compared\nto their counterparts on (011) and (111)-oriented STO. On the other\nhand, the orientation-dependent SRO films exhibit tunable plasmonic\nENZ, increased metallicity, flexible optical conductivity, and customizable\noptical transparency in the near-infrared region. These results not\nonly provide a straightforward and effective pathway for achieving\ntunable PMA and transparent plasmonic states in epitaxial oxide layers\nbut also hold the potential to develop state-of-the-art oxide-based\noptospin–orbit coupled spintronic switching and memory devices.