Investigating Interfacial Coupling in La_2/3Sr_1/3MnO₃/La_1/3Sr_2/3FeO₃ Thin Film Heterostructures

Spintronics are an energy efficient alternative to conventional electronics because of their use of electron spin to carry information. Metals have traditionally been studied for these applications, but there is growing interest in studying alternative materials like complex oxides to further improve efficiency and functionality of spin-based devices. In particular, the perovskite oxides are widely known for their strong coupling and rich phase diagrams, and recent work has shown that they can perform comparably to or better than conventional metals in spin-based structures.

As a step towards all-oxide spintronics, we investigate magnetic properties and interlayer coupling in La2/3Sr1/3MnO3 (LSMO) / La1/3Sr2/3FeO3 (LSFO) heterostructures as a function of temperature and LSFO thickness. We observe clear magnetic coupling between the ferromagnetic (FM) LSMO and antiferromagnetic (AFM) LSFO in the form of an exchange bias and sharp increases in coercivity. X-ray magnetic circular dichroism (XMCD) measurements reveal novel temperature dependence in LSMO/LSFO that is not present in individual films. Finally, resistance measurements show dramatic changes in bilayer resistance below 100 K, a temperature regime where we have previously observed LSFO’s known AFM and charge order disappear. All together, these measurements speak to the rich coupling present in these perovskite oxide heterostructures that could offer greater efficiency and tunability in spintronics.