Speaker
Description
We investigate the complex interplay of competing phases in bulk La$_{5/8−x}$Pr$_x$Ca$_3/8$MnO$_3$ (LPCMO) to demonstrate the coexistence of volatile and non-volatile multilevel resistive switching (RS) within a single device. In this system, ferromagnetic metallic (FM-M) and chargeordered insulating (COI) phases spatially coexist across a broad ∼160 K temperature window. While volatile RS is driven by a reversible, electrically induced metal-insulator transition, the non-volatile RS is governed by the thermal history of the FM volume fraction. Specifically, voltage pulses that heat the device into a critical 90–210 K window permanently alter the phase fraction, modulating the resistance by up to seven orders of magnitude (∼300 Ω to ∼109 Ω). The metallic state is fully recoverable by cycling the temperature above the charge-ordering threshold (∼210 K). To quantitatively capture this phase-fraction control, we implement a Preisach–percolation framework. Calibrated directly from experimental R–T hysteresis loops without free parameters, the model extracts domain switching distributions and utilizes a percolation threshold of $p_c = 0.65$ to successfully predict both macroscopic resistance at 2 K and magnetization at 5 K following specific thermal pathways. Ultimately, we demonstrate the stabilization of three distinct, highly reproducible resistance states over 25 cycles with ratios exceeding $10^3$, showcasing phase-fraction engineering as a robust mechanism for multilevel memory in correlated oxides.
Keywords: resistive switching, phase separation, Preisach model, percolation theory, LPCMO, neuromorphic computing.
Acknowledgements
This work was conducted in collaboration with Diego Carranza-Celis (Universidad de los Andes), Pavel Salev (University of Denver), Ali C. Basaran (General Atomics), and Ivan K. Schuller (UC San Diego). J.G.R. acknowledges support from the Facultad de Ciencias and Vicerrectoría de investigaciones of Universidad de los Andes. This work was also supported by Project No. INV2021-128-2313 of the Faculty of Science at Universidad de los Andes, Bogotá, Colombia. The research at University of California, San Diego was supported by the U.S. Department of Energy’s Office of Basic Energy Science, under Grant No. DE-FG02-87ER45332.
