Escalated Phase Separation Driven Enhanced Magnetoresistance in Manganite/Iridate Epitaxial Heterostructures

Phase separation in manganites leads to unique magnetic and electronic properties. 50% Ca‐doped LaMnO3 (LCMO), at the boundary of ferromagnetic (FM) and antiferromagnetic (AFM) states in La1‐xCaxMnO3 (0 ≤ x ≤ 1), is an ideal system to study phase separation behavior. The investigation reveals the effect of a 5d‐metal perovskite SrIrO3 (SIO) on the phase separation, magnetic, and magnetoresistance (MR) properties of LCMO. Single‐layer and bilayer LCMO films, both appear purely ferromagnetic along the in‐plane (IP) magnetic field direction, but show the tendency of temperature‐dependent ferromagnetic and antiferromagnetic or charge‐ordered (CO) phase separation with the out‐of‐plane (OOP) applied field. The MR, and colossal magnetoresistance (CMR), observed in LCMO/SIO bilayers are two orders and an order of magnitude (in %) larger, respectively than that in the single‐layer film. The coexistence of FM and AFM/CO phases is responsible for the CMR and MR enhancement in the LCMO/SIO bilayer, pointing toward the importance of the phase separation and competition of both the individual materials in enhancing their magnetic and electronic properties. This work examines the effect of heavy metal compound SrIrO3 (SIO) on the magnetic phase separation behavior of La0.5Ca0.5MnO3 (LCMO) thin films. The investigation reveals that SIO promotes the coexistence of ferromagnetic (FM) and antiferromagnetic (AFM) phases in LCMO and hence helps in greatly enhancing the magnetoresistance (MR), and colossal magnetoresistance (CMR) of the LCMO/SIO bilayer.