Strain engineering induced interfacial self-assembly and intrinsic exchange bias in a manganite perovskite film

Abstract

The control of complex oxide heterostructures at atomic level generates a rich spectrum of exotic properties and unexpected states at the interface between two separately prepared materials. The frustration of magnetization and conductivity of manganite perovskite at surface/interface which is inimical to their device applications, could also flourish in tailored functionalities in return. Here we prove that the exchange bias (EB) effect can unexpectedly emerge in a (La,Sr)MnO3 (LSMO) “single” film when large compressive stress imposed through a lattice mismatched substrate. The intrinsic EB behavior is directly demonstrated to be originating from the exchange coupling between ferromagnetic LSMO and an unprecedented LaSrMnO4-based spin glass, formed under a large interfacial strain and subsequent self-assembly. The present results not only provide a strategy for producing a new class of delicately functional interface by strain engineering, but also shed promising light on fabricating the EB part of spintronic devices in a single step.

Electrical control of magnetism in oxides

“…[33][34][35] The strain-mediated electrical control of magnetism is considered to be the first attempt at designing a ME coupling in artificial FM/FE particulates and phase segregated ceramics, [36] and this approach has received renewed attention more recently. [37,38] This type of ME coupling were also widely reported in magnetic thin films (e.g.…”

Enhancing interfacial magnetization with a ferroelectric

“…Considering these facts, PNR has the capability to nondestructively probe the influence of electrostatic doping upon the suppressed surface and interfacial magnetism of manganite thin films, of which the origin has been difficult to isolate ( Figure 1). Previously, this behavior has been attributed to discontinuation of oxygen octahedra at the interface, 10 compositional changes, 18,22 electronic reconstruction due to polar discontinuity 11,24 or modified orbital occupancy near the film surface. 9,14 The latter explanation provided by x-ray resonant magnetic scattering and theoretical techniques is indeed compelling.…”

“…[16][17][18] However, these techniques measure bulk properties rather than behavior specific to a few nanometers, e.g. interfacial magnetism.…”

Electrical Manipulation of Orbital Occupancy and Magnetic Anisotropy in Manganites

“…[1][2][3] The interaction between lattice, charge, spin, and orbital degrees of freedom is found to play a direct and crucial role in the performance of electronic materials, displaying a rich spectrum of exotic phenomena. [4][5][6] The electric field effect with advantages of low power consumption and high controllability offers an effective and reversible route to confine the lattice, charge, and spin (as illustrated in Figure 1): (a) the piezoelectric effect in crystalline materials without inversion symmetry has bridged electric field and lattice for more than 130 years; [7] (b) the field-effect transistor (FET) provided a classic model for the manipulation of carrier density by electrical means, constituting the cornerstone of the semiconductor industry; [8] (c) the magnetization switching is driven reversibly by applied electric fields, which is expected to have a great technological impact on information storage. [9,10] However, electrical control of the missing member-orbital degree of freedom, whose small perturbations would lead to giant responses in the electric and magnetic properties, [11,12] has thus far remained an interesting concept lacking experimental insight.…”