# Magnetism and nonlinear charge transport in NiFe2O4/{\gamma}-Al2O3/SrTiO3 heterostructure: Toward Spintronic Applications

## TL;DR

This study demonstrates the synthesis of a NiFe2O4/{\

## Contribution

It introduces a low-temperature method to create a ferrimagnetic NiFe2O4 layer on a heterostructure that maintains high mobility and exhibits magneto-electronic rectification for spintronics.

## Key findings

- High-mobility 2DEG at the interface
- Metallic behavior down to cryogenic temperatures
- Magnetic diode with rectification enhanced by magnetic field

## Abstract

We present the synthesis and study of the magnetic and electronic properties of NiFe2O4/{\gamma}-Al2O3/SrTiO3 heterostructure. The {\gamma}-Al2O3/SrTiO3 interface hosts a high-mobility two-dimensional electron gas (2DEG) with large spin-orbit coupling, making it promising for spintronics applications if it can be coupled to a suitable source of spin currents. Here, we synthesize a ferrimagnetic insulating NiFe2O4(001) layer on {\gamma}-Al2O3(001)/SrTiO3(001) using a low-temperature reactive sputtering at 150 deg C without compromising the mobility and charge carrier density of the 2DEG at the {\gamma}-Al2O3(001)/SrTiO3(001) interface. The sheet resistance of both {\gamma}-Al2O3/SrTiO3 and NiFe2O4/{\gamma}-Al2O3/SrTiO3 exhibits metallic behavior down to cryogenic temperatures, with a low temperature upturn driven by the Kondo-like scattering. Most importantly, NiFe2O4/{\gamma}-Al2O3/SrTiO3 behaves as a magnetic diode at low temperatures, and its rectification performance increases significantly with increasing magnetic field strength giving rise to a robust magneto-electronic rectification effect at low temperatures, which provides a first step towards the development of all-oxide heterostructures capable of efficient spin-charge conversion.

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Source: https://tomesphere.com/paper/2508.20710