Correlation-driven eightfold magnetic anisotropy in a two-dimensional oxide monolayer

Abstract

Engineering magnetic anisotropy in two-dimensional systems has enormous scientific and technological implications. The uniaxial anisotropy universally exhibited by two-dimensional magnets has only two stable spin directions, demanding 180° spin switching between states. We demonstrate a previously unobserved eightfold anisotropy in magnetic SrRuO3 monolayers by inducing a spin reorientation in (SrRuO3)1/(SrTiO3)N superlattices, in which the magnetic easy axis of Ru spins is transformed from uniaxial 〈001〉 direction (N < 3) to eightfold 〈111〉 directions (N ≥ 3). This eightfold anisotropy enables 71° and 109° spin switching in SrRuO3 monolayers, analogous to 71° and 109° polarization switching in ferroelectric BiFeO3. First-principle calculations reveal that increasing the SrTiO3 layer thickness induces an emergent correlation-driven orbital ordering, tuning spin-orbit interactions and reorienting the SrRuO3 monolayer easy axis. Our work demonstrates that correlation effects can be exploited to substantially change spin-orbit interactions, stabilizing unprecedented properties in two-dimensional magnets and opening rich opportunities for low-power, multistate device applications.

Symmetry-Driven Spin-Wave Gap Modulation in Nanolayered SrRuO3/SrTiO3 Heterostructures: Implications for Spintronic Applications

“…Particularly, a SrRuO3/SrTiO3 superlattice (SRO/STO SL) is an ideal prototype for selectively controlling the crystalline symmetry and magnetic anisotropy of SRO. [28][29][30] In this study, we demonstrate the customization of the spin-wave gap in SRO through artificial crystalline symmetry control. We fabricated SRO/STO SLs using pulsed laser epitaxy with atomic-scale precision.…”

Manipulating Berry curvature of SrRuO3thin films via epitaxial strain

“…Transition metal oxide SrRuO 3 provides an ideal platform to investigate Berry curvature, because it is a 4d metallic ferromagnet with a sizable SOC (17)(18)(19)(20), in which the AHE mainly arises from the Berry curvature of its electronic band structure (11,21,22). Due to the strong coupling between lattice distortions and electronic structure in transition metal oxides, previous studies have already revealed that epitaxial strain has profound effects on magnetic properties of SrRuO 3 films (23)(24)(25)(26)(27)(28)(29)(30)(31)(32). These results suggest that epitaxial strain might be an effective approach to manipulating Berry curvature and related AHE in SrRuO 3 thin films, which, however, has not been comprehensively investigated yet.…”

Interfacial engineering manipulation of magnetic anisotropy evolution via orbital reconstruction in low-dimensional manganite superlattices

“…To get a quantitative description of the PMA strength, the effective anisotropy constant (K eff ) was quantitatively estimated by the shadow area between the OOP and IP magnetization curves as shown Fig. S8 [43]. The negative and positive values of K eff refer to the IP and OOP magnetic anisotropy, respectively.…”