Work

Near Room‐Temperature Ferromagnetic Phase Achieved in 4 d Ruthenate via Interfacial Ferrimagnetic Coupling and Octahedral Rotation Engineering

Year: 2025

Type: article

Abstract: Transition metal oxides (TMOs) simultaneously possessing strong spin‐orbit coupling, near room‐temperature ferromagnetism, and excellent conductivity are scarce while they show great potential applications in oxide spintronics. Here, a TMO with all these features is reported, existing as an interfacial phase in the 4 d Ca 0.5 Sr 0.5 RuO 3 layer sandwiched by two LaMnO 3 layers. This phase is well conductive and ferromagnetic in a wide temperature range, with the highest Curie temperature of ≈275 K among the 4 d /5 d ‐TMOs. Particularly, this interfacial phase shows a considerably improved saturation magnetization (≈2 µ B /Ru, twice that of the bulk counterpart), and a greatly reduced coercive force. All these features are highly desired by the application of spin‐orbit torque. Due to the presence of strong spin‐orbit coupling, such a Ca 0.5 Sr 0.5 RuO 3 interfacial phase exhibits a significantly larger anomalous Hall conductivity than the typical 3 d oxide ferromagnet La 2/3 Sr 1/3 MnO 3 near room temperature. Analyses based on the techniques of X‐ray magnetic circular dichroism, polarized‐neutron reflectometry, and scanning transmission electron microscopy reveal a magnetic exchange interaction between the interfacial phases of Ca 0.5 Sr 0.5 RuO 3 and LaMnO 3 and an obvious expansion of the interfacial Mn─O─Mn bond angle, stabilizing the high‐temperature ferromagnetic state of the CSRO/LMO interface.

Source: Advanced Science

DOI: 10.1002/advs.202502613