Large Magnetic Proximity Effect in Manganite Oxide Heterostructures

The fabrication of spintronic devices necessitates the use of multi-layer structures made up of diverse magnetic materials. Such magnetic structures lead to a wide range of interface effects, prominent among which is the proximity effect. Manganite oxide thin film heterostructures are potential candidates for a comprehensive exploration of these proximity effects, primarily because manganites showcase emergent phenomena due to the dynamic interplay among charge, spin, orbital, and lattice degrees of freedom [1]. Some of their fascinating properties are colossal magnetoresistance and metal-insulator transitions. These properties arise from the intricate interactions among charge carriers, spin ordering, and lattice distortions, and they can be modulated by external stimuli like magnetic or electric fields. The physical attributes of manganites, such as Sm1-xSrxMnO3 (SSMO), undergo significant changes with alterations in the Sr doping percentage. Depending on the doping ratio, SSMO can exhibit ferromagnetic, antiferromagnetic, or even mixed magnetic phases [2]. The extensive variety of phenomena that can be tuned based on Sr concentration in SSMO highlights its scientific importance and makes it a compelling subject for the study of diverse properties [3, 4]. In this study, we investigated the magnetic proximity effect in SSMO bilayer and tri-layer heterostructures. Initially, we deposited a single layer of ferromagnetic metal (FMM) and an antiferromagnetic insulator (AFI) onto a SrTiO3 (STO) substrate using the pulsed laser deposition (PLD) technique. Their magnetic attributes were assessed with a SQUID magnetometer, and the results were consistent with earlier reports. Subsequently, we laid down a bi-layer stack of FMM/AFI and a tri-layer configuration of AFI/FMM/AFI on the STO substrate. We observed a marked increase in magnetic moment across these structures, indicating that the magnetic proximity effect in the heterostructures was the main contributor. In conclusion, manganite heterostructures present a promising avenue for further exploration of novel electronic and magnetic phenomena at their interfaces. References: 1. Y. Tokura, Reports Prog. Phys. 69, 797 (2006). 2. Kurbakov et al., Journal of Physics: Condensed Matter. 20, 104233 (2008). 3. Bhagwati Prasad, et al.”, Advanced Materials 27, 3079 (2015). 4. Bhagwati Prasad and M. G. Blamire, Appl. Phys. Lett. 109, 132407 (2016).