RETRACTED ARTICLE: Oxygen vacancy-induced enhancement in magnetism and magneto-transport properties in Sm0.55Sr0.45MnO3 thin films

Polycrystalline Sm0.55Sr0.45MnO3 (SSMO) thin films (thickness ~ 100 nm) were prepared on nearly lattice matching LSAT (100) single crystal substrates by ultrasonic nebulized spray pyrolysis, and impact of oxygen vacancy on magnetic and high field magneto-transport properties are investigated. The X-ray diffraction θ‒2θ scan reveals that these films (i) have very good crystallinity, (ii) oriented along out-of-plane c-direction, and (iii) are under small tensile strain. The impact of oxygen vacancy results into (i) higher value of paramagnetic insulator (PMI) to ferromagnetic metal (FMM) transition temperature, i.e., TC/TIM, (ii) sharper PMI–FMM transition, as confirmed by higher temperature coefficient of resistance (TCR), (iii) higher value of magnetization and magnetic saturation moment, and (iv) higher value of magnetoresistance. The magnetic state at T < TC is akin to cluster glass, which is formed by the presence of charge-ordered–antiferromagnetic clusters in the ferromagnetic matrix. We suggest here that oxygen vacancy favors ferromagnetic metal phase while oxygen vacancy annihilation leads to antiferromagnetic–charge-ordered insulator phase. The observed results have been explained in terms of the growth condition-induced variations in the dimensionality and fractions of the competing ferromagnetic metal and antiferromagnetic–charge-ordered insulator phases.