Strain tuning lithium ferrite thin films through Al substitution

In order to realize next generation spintronics that utilize spin-waves to transport magnetic information without dissipative charge currents, we must develop high-quality, ultra-thin film magnetic insulators that combine low magnon damping and perpendicular magnetic anisotropy (PMA). Ferrimagnetic spinel structure Li0.5AlxFe2.5-xO4 (LAFO) has been identified as a material that combines these properties, making it an important material for further analysis towards the goal of creating highly energy-efficient electronics. To determine the optimal composition of LAFO, we have investigated an array of compositions deposited on MgGa2O4 substrates with Al substitution ranging from x=0.5-1.0. Al substitution modifies the saturation magnetization and magnetic anisotropy while maintaining ultra-low Gilbert damping parameters ranging from 2x10-4 to 1x10-3.Through this work we have identified LAFO composition x=0.7 which combines ultra-low damping (~2x10-4), PMA and very small saturation fields, thus making it very promising for spintronic applications.