Regensburg 2025 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 9: (Multi)ferroic States: From Fundamentals to Applications (IV)

KFM 9.1: Talk

Tuesday, March 18, 2025, 11:45–12:00, H9

Investigating Self-Heating of Conducting Domain Walls Using Scanning Thermal Microscopy — •Lindsey Lynch, Kristina Holsgrove, Marty Gregg, and Raymond McQuaid — Queen's University Belfast

Domain walls (DWs) in ferroelectrics are an exciting category of reconfigurable functional interface, with properties that can differ from bulk. Lab-level transistor [1] and memristor devices [2] have been demonstrated, where functionality is derived entirely from electrically conducting DWs. Here, the DWs perform the equivalent role of conductive nanofilaments in metal-oxide resistive switching memories. While self-heating and local temperature are important factors in oxygen-vacancy based resistive switching [2,3], much less is known about the intrinsic self-heating of domain walls and its influence on device operation. We have been investigating the electrothermal properties of LiNbO3 domain wall devices using Scanning Thermal Microscopy (SThM). This involves using the scanning probe as a mobile nanoscale temperature sensor to map self-heating in domain wall devices. Temperature hot spots on the order of 10K are detected and PFM corroborates that their origin is due to sub-surface domain wall heating. Since heat spreading occurs within the surrounding ferroelectric film and top electrode, the measured surface temperatures likely represent a lower bound for the intrinsic rise in domain wall temperature.

[1] Nat. Commun. 11, 2811 (2020). [2] Adv. Funct. Mater. 30, 2000109 (2020). [3] Sci. Adv. 8, eabk1514 (2022). [4] ACS Appl. Mater. Interfaces 14, 29025 (2022).

Keywords: ferroelectrics; domain walls; piezoresponse force microscopy; joule heating; scanning thermal microscopy