SEMINAR LMGP - 04.05.2021 - Carlos MONCASI

"Structure-properties relations for manganite memristive devices"


Carlos MONCASI
PhD student,
Université Grenoble Alpes, CNRS, Grenoble INP, LMGP, Grenoble
 

Resistive Switching (RS) devices, which can reversibly change their resistance between at least two different states, are promising candidates for the next generation of non-volatile memories: Resistive Random Access Memories (ReRAM). Furthermore, the same memristive properties have gained attention to develop non Von-Neumann logics for neuromorphic computing. Perovskite materials such as (La,Sr)MnO₃ (LSM) exhibit resistive switching triggered by the drift of oxygen vacancies. RS and other functional properties in thin films, rely on the microstructure. Therefore, we assess the role of strain in thin films on RS.

Strain in epitaxial thin films can be induced by lattice mismatch with the substrate. LSM films were grown by pulsed injection metal-organic chemical vapour deposition (PI-MOCVD) on two different single crystal substrates, namely SrTiO₃ (STO) and LaAlO₃ (LAO), to induce in-plane tensile and compressive strain, respectively. Devices of Ti/LSM\Pt in top-top configuration were microfabricated on LSM/STO and LSM/LAO. Whereas the devices on both substrates show reproducible and analog response, the devices on LSM/LAO (in-plane compressive strain) show larger resistance ratios (HRS/LRS) and longer retention times. Understanding of these results will allow further comprehension of the LSM nanoionic properties and eventually lead to the optimization of manganite memristive devices.