Pinning Strength‐Induced Spin Relaxation Across Oxide Interfaces

We investigated the impact of interface defect pinning strength on spin relaxation and magnetoresistance (MR) in bare NiFe 2 O 4 (NFO), bare CoFe 2 O 4 (CFO), NFO/Si junction and CFO/Si heterojunction devices. The impact of band alignment and interfacial defect states on charge and spin transport was investigated using current–voltage ( I – V ) characteristics obtained under various magnetic fields. Compared to the CFO/Si device, the NFO/Si heterojunction shows better interface quality with reduced leakage current, indicating enhanced spin‐polarised transport. Hence, a sharp large peak of negative MR has been observed for NFO bare device at low bias voltage. Enhanced leakage current and defect density extracted from the thermionic emission model indicate higher spin decoherence and hence a positive MR contribution for CFO devices. Manipulation of MR through defect state modification can be used for spintronic memory device development using such functional materials and heterojunctions.