Abstract
films with the thickness () ranging from 8 to 157 nm, grown on (001)-oriented substrates by rf magnetron sputtering, undergo a secondary metal-insulator transition (SMIT) below a critical temperature when . The transition temperature gradually increases from 25 K at 63 nm to 108 K at 157 nm with increasing film thickness. Raman spectra demonstrate that the occurrence of the SMIT is attributed to the reduction of the Jahn-Teller distortion. Further investigations indicate that the SMIT can take place in the ferromagnetic and -type antiferromagnetic () spin structures, which is ascribed to the generation of two-dimensional conduction bands in the planes through the double-exchange interaction. This work suggests that the SMIT provides a pathway to study multiple metal-insulator transitions and demonstrates the potential applications in spintronic devices.
- Received 4 October 2021
- Revised 10 May 2022
- Accepted 27 July 2022
DOI:https://doi.org/10.1103/PhysRevB.106.064103
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