Magnetism and nonlinear charge transport in NiFe2O4/γ-Al2O3/SrTiO3 heterostructure: Toward Spintronic Applications

Abstract

We present the synthesis and study of the magnetic and electronic properties of NiFe2O4/γ-Al2O3/SrTiO3 heterostructure. The γ-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 γ-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 γ-Al2O3(001)/SrTiO3(001) interface. The sheet resistance of both γ-Al2O3/SrTiO3 and NiFe2O4/γ-Al2O3/SrTiO3 exhibits metallic behavior down to cryogenic temperatures, with a low temperature upturn driven by the Kondo-like scattering. Most importantly, NiFe2O4/γ-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.

37 pages, 6 figures

References in corpus (14)

• Highly efficient and tuneable spin-to-charge conversion through Rashba coupling at oxide interfaces
• A high-mobility two-dimensional electron gas at the heteroepitaxial spinel/perovskite complex oxide interface of γ-Al2O3/SrTiO3
• Half-Metallic Ferromagnetism in the Heusler Compound Co${}_2$FeSi revealed by Resistivity, Magnetoresistance, and Anomalous Hall Effect measurements
• Enhanced ferrimagnetism in auxetic NiFe2O4 in the crossover to the ultrathin film limit
• Giant tunability of the two-dimensional electron gas at the interface of gamma-Al2O3/SrTiO3
• Ferroelectric order associated with an ordered occupancy at the octahedral site of the inverse spinel structure of multiferroic NiFe2O4
• Suppression of the fieldlike spin-orbit torque efficiency due to the magnetic proximity effect in ferromagnet/platinum bilayers
• All-electrical measurement of spin injection in a magnetic $p$-$n$ junction diode
• Diodes with Breakdown Voltages Enhanced by the Metal-Insulator Transition of LaAlO${}_3$-SrTiO${}_3$ Interfaces
• Enhancement in Thermally Generated Spin Voltage at Pd/NiFe${}_2$O${}_4$ Interfaces by the Growth on Lattice-Matched Substrates
• Vectorial observation of the spin Seebeck effect in epitaxial NiFe${}_2$O${}_4$ thin films with various magnetic anisotropy contributions
• Coexistence of high electron-mobility, unpaired spins, and superconductivity at high carrier density SrTiO${}_3$-based interfaces
• Leveraging high fluence and low pressure for pulsed laser deposition of high-mobility $\gamma$-Al${}_2$O${}_3$/SrTiO${}_3$ heterostructure growth
• Ferromagnetic Two-dimensional Electron Gases with Magnetic Doping and Proximity Effects