Resistive Switching in Ferroelectric Bi<sub>2</sub>FeCrO<sub>6</sub> Thin Films and Impact on the Photovoltaic Effect
David Sebastian Walch, Yeseul Yun, Niranjan Ramakrishnegowda, Lutz Mühlenbein, Andriy Lotnyk, Cameliu Himcinschi, Akash Bhatnagar
Abstract
Abstract The multiferroic character of Bi 2 FeCrO 6 (BFCO), that is, the coexistence of ferroelectricity and ferromagnetism, has been predicted and demonstrated in different studies. Intriguingly, the material system also exhibits a reduced band gap, in addition to bulk‐driven photovoltaic effect. The co‐existence of all these attributes in a single system is a rare occurrence and paves way to a multitude of practical applications, with ferroelectric solar cell as one of them. In this work, epitaxially grown BFCO thin films, deposited with pulsed laser deposition on single crystalline SrTiO 3 (STO) substrates, reveal a self‐ordered ionic arrangement which is proven with X‐ray and transmission electron micrcoscope (TEM) measurements. A lowered band gap and a higher conductivity lead to a superior photovoltaic performance compared to a BiFeO 3 (BFO) reference film. Scanning probe microscopy (SPM) is used to test locally the ferroelectric switching properties. Poling with electric field not only caused a reliable change in the state of polarization, but also resulted in substantial changes in the resistance of the regions. Macroscopic measurements using transparent In 2 O 3 :Sn (ITO) electrodes demonstrate a bi‐directional multi‐stage resistive switching, which in turn influences the photovoltaic performance of the heterostucture.