${\mathrm{Ni}\mathrm{Co}}_2{\mathrm{O}}_4$ (NCO), with an inverse spinel structure, stands out for diverse spintronic properties like perpendicular magnetic anisotropy (PMA) and anomalous Hall effect (AHE). Precise control of these properties is essential for ferrimagnetic half-metallic NCO. Here, we report the effective modulation of PMA and AHE in NCO thin films through $\mathrm{Fe}$ doping. We demonstrate that the magnetic anisotropy energy (MAE) reaches $1.03\mathrm{MJ}/{\mathrm{m}}^3$ for ${\mathrm{Ni}\mathrm{Co}}_{1.6}{\mathrm{Fe}}_{0.4}{\mathrm{O}}_4$ films with a robust PMA at room temperature, an order of magnitude enhancement over pristine NCO films and superior to most known PMA-based magnetic structures. A higher Curie temperature can be obtained in ultrathin ${\mathrm{Ni}\mathrm{Co}}_{2-x}{\mathrm{Fe}}_x{\mathrm{O}}_4$ films, compared to the pristine NCO films, due to an enhancement of the superexchange interaction from $\mathrm{Fe}$. We also observe the high tunability of AHE in ${\mathrm{Ni}\mathrm{Co}}_{2-x}{\mathrm{Fe}}_x{\mathrm{O}}_4$ films, with its underlying mechanism undergoing a crossover as x increases, transitioning from extrinsic skew scattering to intrinsic Berry curvature contribution, and finally to a bad-metal-hopping regime. This tunability of AHE is rare in other magnetic systems. These findings provide a pathway for engineering NCO-based ferrimagnetic spintronic platforms with tailored functionalities.

Close

PrevNext

View figure in article

• Anomalous Hall effect
• Magnetic anisotropy
• Ferrimagnets
• Magnetic thin films
• Magnetization measurements
• Resistivity measurements
• X-ray absorption spectroscopy
• X-ray magnetic circular dichroism