Enhanced Interface-Driven Perpendicular Magnetic Anisotropy by Symmetry Control in Oxide Superlattices

Abstract

Perpendicular magnetic anisotropy (PMA) has recently been shown to emerge at interfaces of 3d and 5d transition-metal oxides (TMOs). However, strategies to systematically stabilize such interface-driven PMA still remains elusive, hindering further applications of this design approach. Here, tuning crystal symmetry is shown to be an effective means to engineer this interfacial phenomenon. The evolution of PMA strength as a function of ferromagnetic oxide thickness quantitatively reveals the competition between volume-and interface-specific contributions that determine the magnetic anisotropy. By applying different degrees of epitaxial strain, the relative contributions to PMA are modulated, clearly revealing their correlations with crystal symmetries. To be more specific, the volume anisotropy energy is found to be correlated with the tetragonal distortion of the ferromagnetic layer, while the interface anisotropy energy is mainly modulated by the octahedral tilting at the interface. With these insights, superlattices with enhanced interface-driven PMA and higher Curie temperature are realized. These findings reveal a route to engineering interface-driven PMA and associated magnetic phenomena in TMO heterostructures for future spintronic applications.

Superconductivity assisted change of the perpendicular magnetic anisotropy in V/MgO/Fe junctions

“…Control of out-of-plane (OOP) anisotropies in ultra thin ferromagnetic multilayer films have revolutionized magnetic storage and spintronics technologies by mitigating the impact of the demagnetizing energy as the bit and magnetic tunnel junction sizes diminished 1 , 2 . Tuning of perpendicular magnetic anisotropy (PMA) by careful selection of structure design 3 , 4 and size 5 has been among the main challenges of spintronics. Besides the variation of the ferromagnet thickness and interface with oxides, OOP magnetisation reorientation can be achieved by a temporary reduction of the IP-OOP barrier using, for example, heat and microwave pulses 6 , 7 or a combination of magnetic field and low temperature 8 .…”

Tunable Magnetic Anisotropy in Patterned SrRuO3 Quantum Structures: Competition between Lattice Anisotropy and Oxygen Octahedral Rotation

“…We attribute the variable magnetic anisotropy of fabricated nanodot arrays to the altered intrinsic magnetocrystalline anisotropy. Generally, the effective uniaxial anisotropy energy K μ in a heterostructure can be described as the following relation [ 43,44 ] where K v and K i / t correspond to the volume anisotropy energy and the contribution from the interface in a ferromagnetic layer with a thickness t . For as‐grown SRO thin films with perpendicular uniaxial magnetic anisotropy, the contributions from the volume magnetocrystalline anisotropy K v and the interfacial crystalline anisotropy K i / t cannot be decoupled, because STEM results reveal that the lattice structure controlling the magnetocrystalline anisotropy remains unchanged throughout the SRO layer.…”

“…We attribute the variable magnetic anisotropy of fabricated nanodot arrays to the altered intrinsic magnetocrystalline anisotropy. Generally, the effective uniaxial anisotropy energy K μ in a heterostructure can be described as the following relation [43,44]…”

Electric field-controlled reversible high-temperature perpendicular magnetic anisotropy in cobaltate–manganite heterostructures

“…Lately, researchers have discovered that interface engineering can be an effective method to control the magnetic anisotropy of LSMO films. [9][10][11][12][13] Liao et al achieved the realignment of lateral magnetic anisotropies in LSMO films by utilizing interface octahedral coupling. 9 However, the major problem is the fixed orientation of the magnetic anisotropy once the films are fabricated, limiting the commercialization of their applications in devices.…”