Data for: Magnetism and Nonlinear Charge Transport in NiFe2O4/γ-Al2O3/SrTiO3 Heterostructure: Toward Spintronic Applications

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 spintronic and nano-electronic device applications if it can be coupled to a suitable source of spin currents. For efficient spin-charge conversion, a ferromagnetic insulator as a spin current source is more advantageous than a metallic/semiconducting ferromagnet. Here, we synthesize a ferrimagnetic insulating NiFe2O4(001) layer on γ-Al2O3(001)/SrTiO3(001) using low-temperature reactive sputtering at 150 ℃ without compromising the mobility and charge carrier density of the 2DEG at the γ-Al2O3(001)/SrTiO3(001) interface. While γ-Al2O3(8nm)/SrTiO3 is nonmagnetic, NiFe2O4(52nm)/γ-Al2O3(8nm)/SrTiO3 shows well-defined magnetic hysteresis loop at room temperature as well as at low temperatures. The sheet resistance of both γ-Al2O3(8nm)/SrTiO3 and NiFe2O4(52nm)/γ-Al2O3(8nm)/SrTiO3 exhibits metallic behavior down to cryogenic temperatures, with a low temperature upturn driven by the combined effect of Kondo-like scattering and weak antilocalization. Most importantly, NiFe2O4(52nm)/γ-Al2O3(8nm)/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 nanoscale all-oxide heterostructures capable of efficient spin-charge conversion.