Atomically sharp oxide heterostructures exhibit a range of novel physical phenomena that do not occur in the parent bulk compounds including conducting, superconducting, and magnetic states. We present a new emergent phenomenon at the LaMnO3/SrTiO3 interface in which an antiferromagnetic insulator abruptly transforms into a superparamagnetic state. Above a critical thickness of LaMnO3 of five unit cells, our scanning nanoSQUID-on-tip microscopy  shows spontaneous formation of isolated magnetic islands with in-plane moment of 10^4 to 10^5 μ_B with characteristic diameter of 10 to 50 nm . The nanoscale islands display superparamagnetic dynamics of random moment reversals by thermal activation or in response to an in-plane magnetic field. We propose a charge reconstruction model of the polar LaMnO3/SrTiO3 heterostructure which describes a sharp emergence of thermodynamic phase separation leading to nucleation of metallic ferromagnetic islands in an insulating antiferromagnetic matrix. The model suggests that a gate tunable superparamagnetic-ferromagnetic transition can be induced, holding potential for applications in magnetic storage and spintronics.
 D. Vasyukov et al., Nature Nanotechnology 8, 639 (2013).
 Y. Anahory, L. Embon, C. J. Li, S. Banerjee, A. Meltzer, H. R. Naren, A. Yakovenko, J. Cuppens, Y. Myasoedov, M. L. Rappaport, M. E. Huber, K. Michaeli, T. Venkatesan, Ariando, and E. Zeldov,
Nat. Commun. 7, 12566 (2016).
Eli Zeldov, "Emergent nanoscale superparamagnetism and electronic phase separation at oxide interfaces (Conference Presentation)," Proc. SPIE 10357, Spintronics X, 103570W (Presented at SPIE Nanoscience + Engineering: August 07, 2017; Published: 19 September 2017); https://doi.org/10.1117/12.2277911.5581366891001.
Conference Presentations are recordings of oral presentations given at SPIE conferences and published as part of the conference proceedings. They include the speaker's narration along with a video recording of the presentation slides and animations. Many conference presentations also include full-text papers. Search and browse our growing collection of more than 14,000 conference presentations, including many plenary and keynote presentations.