Ru‐Doping‐Induced Spin Frustration and Enhancement of the Room‐Temperature Anomalous Hall Effect in La_2/3Sr_1/3MnO₃ Films

Abstract

In transition‐metal‐oxide heterostructures, the anomalous Hall effect (AHE) is a powerful tool for detecting the magnetic state and revealing intriguing interfacial magnetic orderings. However, achieving a larger AHE at room temperature in oxide heterostructures is still challenging due to the dilemma of mutually strong spin–orbit coupling and magnetic exchange interactions. Here, Ru‐doping‐enhanced AHE in La2/3Sr1/3Mn1−xRuxO3 epitaxial films is exploited. As the B‐site Ru doping level increases up to 20%, the anomalous Hall resistivity at room temperature can be enhanced from nΩ cm to µΩ cm scale. Ru doping leads to strong competition between the ferromagnetic double‐exchange interaction and the antiferromagnetic superexchange interaction. The resultant spin frustration and spin‐glass state facilitate a strong skew‐scattering process, thus significantly enhancing the extrinsic AHE. The findings can pave a feasible approach for boosting the controllability and reliability of oxide‐based spintronic devices.

Orientation-Driven Strong Perpendicular Magnetic Anisotropy in La0.67Sr0.33MnO3–SrIrO3 Heterostructures

“…This value is 3 orders of magnitude higher than that of bulk LSMO. This finding suggests that constructing magnetic oxide with heavy metal oxide with a large SOC can significantly enhance AHE in the heterosystem, offering a new route for future development of highly detectable oxide-based spin devices …”

Tilted Magnetic Anisotropy with In‐Plane Broken Symmetry in Ru‐Substituted Manganite Films

“…Bulk LSMO has a rhombohedral crystal structure with a pseudocubic lattice parameter of 3.874 Å, which is only slightly larger than the lattice parameter of 3.868 Å of the cubic LSAT substrate. [17] The substitution of Mn by Ru increases the lattice parameter, resulting in increased compressive strain (to be discussed later). [17] The second key observation from Figure 2 is that the (0 1 3) pc film peak ((Q 013 ) ⊥ = 0.7638 Å (−1) ) has shifted upward and the (0 −1 3) pc film peak ((Q (0-13) ) ⊥ = 0.7584 Å (−1) ) has shifted downward with respect to the (± 1 0 3) pc film peaks (( 1) ).…”

Néel Skyrmion Bubbles in La0.7Sr0.3Mn1–xRuxO3 Multilayers

“…By varying the Ru/Mn content from one layer to the next, the inversion symmetry is broken at all interfaces, and a variable strain is introduced in the multilayer system (Ru increases the lattice parameters). Moreover, the strength of the exchange interaction is varied from one layer to the next: The Ru substitution of Mn likely introduces a local antiferromagnetic coupling via superexchange along Ru–O–Mn bonds, − which may lead to symmetry breaking and spin frustration both inside the layers and at the interfaces . The effective magnetic anisotropy is also different in the individual layers, due to the single ion anisotropy affected by the substitution of magnetic ions (Ru vs. Mn) and the modified structure of the Ru-substituted perovskite manganite (varying bond angles and lengths), as well as due to the varying epitaxial strain.…”

“…The effective magnetic anisotropy is also different in the individual layers, due to the single ion anisotropy affected by the substitution of magnetic ions (Ru vs. Mn) and the modified structure of the Ru-substituted perovskite manganite (varying bond angles and lengths), as well as due to the varying epitaxial strain. Consequently, inhomogeneous exchange interaction and frustrated magnetic interactions at the interfaces and an inhomogeneous effective magnetic anisotropy are inherent to these multilayers. Inversion symmetry is broken not only at the interfaces between the layers but possibly also due to inhomogeneous strain distribution and cation off-centering induced by strain .…”

“…Moreover, the strength of the exchange interaction is varied from one layer to the next: The Ru substitution of Mn likely introduces a local antiferromagnetic coupling via superexchange along Ru−O−Mn bonds, 23−25 which may lead to symmetry breaking and spin frustration both inside the layers and at the interfaces. 26 The effective magnetic anisotropy is also different in the individual layers, due to the single ion anisotropy affected by the substitution of magnetic ions (Ru vs. Mn) 24 and the modified structure of the Ru-substituted perovskite manganite (varying bond angles and lengths), as well as due to the varying epitaxial strain. Consequently, inhomogeneous exchange interaction and frustrated magnetic interactions at the interfaces 26 and an inhomogeneous effective magnetic anisotropy are inherent to these multilayers.…”