Interfacial Ferromagnetic Coupling and Positive Spontaneous Exchange Bias in SrFeO3-x/La0.7Sr0.3MnO3 Bilayers

Electrochemically driven physical properties of solid-state materials: action mechanisms and control schemes

The various physical properties recently induced by solid-state electrochemical reactions must be comprehensively understood, and their mechanisms of action should be elucidated. Reversible changes in conductivity, magnetism, and colour have been achieved by combining the redox reactions of d metal ions and organic materials, as well as the molecular and crystal structures of solids. This review describes the electrochemically driven physical properties of conductors, magnetic materials, and electrochromic materials using various electrochemical devices.

Strain-Induced Robust Exchange Bias Effect in Epitaxial La0.7Sr0.3MnO3/LaFeO3 Bilayers

The ground state of correlated electrons in complex oxide films can be controlled by applying epitaxial strain, offering the potential to produce unexpected phenomena applicable to modern spintronic devices. In this study, we demonstrate that substrate-induced strain strongly affects the coupling mode of interfacial magnetic moments in a ferromagnetic (FM)/antiferromagnetic (AFM) system. In an epitaxial bilayer comprising AFM LaFeO3 (LFO) and FM La0.7Sr0.3MnO3 (LSMO), samples grown on a LaAlO3 (LAO) substrate exhibit a larger exchange bias field than those grown on a SrTiO3 substrate. Our results indicate a transition in the alignment of magnetic moments from perpendicular to collinear due to the large compressive strain exerted by the LAO substrate. Collinear magnetic moments at the LSMO/LFO interface generate strong exchange coupling, leading to a considerable exchange bias effect. Thus, our findings provide a method for tailoring and manipulating the orientations of magnetic moments at the FM/AFM heterogeneous interface using strain engineering, thereby augmenting methods for exchange bias generation.

Tuning the Exchange Bias Effect in 2D van der Waals Ferro-/Antiferromagnetic Fe3 GeTe2 /CrOCl Heterostructures

The exchange bias effect is extremely expected in 2D van der Waals (vdW) ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures due to the high-quality interface. CrOCl possesses strong magnetic anisotropy at 2D limit, and is an ideal antiferromagnet for constructing FM/AFM heterostructures to explore the exchange bias effect. Here, the exchange bias effect in Fe₃ GeTe₂ (FGT)/CrOCl heterostructures through both anomalous Hall effect (AHE) and reflective magnetic circular dichroism (RMCD) measurements is studied. In the AHE measurements, the exchange bias field (H_EB ) at 3 K exhibits a distinct increase from ≈150 Oe to ≈450 Oe after air exposure, and such variation is attributed to the formation of an oxidized layer in FGT by analyzing the cross-sectional microstructure. The H_EB is successfully tuned by changing the FGT/CrOCl thickness and the cooling field. Furthermore, a larger H_EB of ≈750 Oe at 1.7 K in FGT/CrOCl heterostructure through RMCD measurements is observed, and it is proposed that the larger H_EB in RMCD measurements is related to the distribution of uncompensated spins at the interface. This work reveals several intriguing phenomena of the exchange bias effect in 2D vdW magnetic systems, which paves the way for the study of related spintronic devices.

Control of the oxygen deficiency and work function of SrFeO3−δ thin films by excimer laser-assisted metal organic decomposition

Excimer laser-assisted metal organic decomposition can provide SrFeO_3−δ films with oxygen deficiency varied by using an appropriate atmosphere and tuning the laser fluence.