Strong perpendicular exchange bias in epitaxial La0.7Sr0.3MnO3:LaFeO3 nanocomposite thin films

Abstract

Strong exchange bias (EB) in perpendicular direction has been demonstrated in vertically aligned nanocomposite (VAN) (La0.7Sr0.3MnO3)1−x : (LaFeO3)x (LSMO:LFO, x = 0.33, 0.5, 0.67) thin films deposited by pulsed laser deposition. Under a moderate magnetic field cooling, an EB field as high as ∼800 Oe is achieved in the VAN film with x = 0.33, suggesting a great potential for its applications in high density memory devices. Such enhanced EB effects in perpendicular direction can be attributed to the high quality epitaxial co-growth of vertically aligned ferromagnetic LSMO and antiferromagnetic LFO phases, and the vertical interface coupling associated with a disordered spin-glass state. The VAN design paves a powerful way for integrating perpendicular EB effect within thin films and provides a new dimension for advanced spintronic devices.

Tunable perpendicular exchange bias in oxide heterostructures

“…Recent advances in metal-oxide heterostructures offer new perspectives for electronic devices based on collective quantum phenomena such as unconventional magnetism, multiferroicity, and superconductivity [7][8][9][10][11] . In particular, exchangebias structures based on ferromagnetic manganates of composition La 1−y Sr y MnO 3 (0.1≤y≤0.5) and different metal-oxide antiferromagnets have been reported [12][13][14] . La 1−y Sr y MnO 3 (LSMO) is a soft ferromagnet, and in thin-film form, it generally orders with magnetization direction in the substrate plane.…”

“…La 1−y Sr y MnO 3 (LSMO) is a soft ferromagnet, and in thin-film form, it generally orders with magnetization direction in the substrate plane. It was recently shown, however, that perpendicular exchange bias can be induced in nanocomposite films of La 0.7 Sr 0.3 MnO 3 and antiferromagnetic LaFeO 3 with active interfaces perpendic-ular to the substrate plane 14 .…”

Microstructure, Magnetic, and Magnetoresistance Properties of La0.7Sr0.3MnO3:CuO Nanocomposite Thin Films

“…Reports have shown that the Curie temperature T c and electrical transport properties of La 0.7 Sr 0.3 MnO 3 (LSMO) thin films (thickness of 22 nm) strongly depend on the substrate-induced biaxial strain . Recently, two-phase vertically aligned nanocomposites (VAN) have been developed, providing an effective way to induce high density of vertical phase boundaries and simultaneously couple the strains in the two phases that are epitaxially grown on a substrate together. , Various VAN morphologies can be achieved, including nanopillars in matrix, ,, nanocheckerboard structures, and other domain structures, , depending on the materials selection and composition. Enhanced LFMR has been observed in highly strained VAN systems such as LSMO:CeO 2 , , LSMO:MgO, , and LSMO:ZnO. , The enhanced LFMR properties were attributed to the strong vertical interface strain coupling built in the vertical coupled interfaces in VAN as well as the phase boundary effects induced by secondary insulating phases (e.g., CeO 2 , MgO, and ZnO, for the above systems).…”

Functional Perovskites: Structure-Properties Correlations

“…9(c)). The disordered spin-glass states at the La0.7Sr0.3MnO3/ LaFeO3 interfaces, related to magnetic frustration, are responsible for the exchange bias effect, where the interfacial frozen spins generate an additional torque on the La0.7Sr0.3MnO3 FM spins (36).…”