Magnetic Coupling in Vertically Aligned BFO-CFO Thin Film Composite and Bilayer BFO-CFO on STO Substrate by Pulsed Laser Deposition
Tahta Amrillah1*, Wei-Cheng Kuo1, Ha Thai Duy1, Yen-Fu Hsiao1, Hau-Wei Fang2, Jenh-Yih Juang1
1Department of Electrophysics, National Chiao Tung University, Hsinchu 30100, Taiwan
2Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu 30100, Taiwan
* presenting author:tahta amrillah,
The magnetic coupling between BFO-CFO/STO self-assembled vertically aligned nanocomposite (VAN) and BFO/CFO/STO bilayers was investigated down to low temperatures. The magnetic transition in BFO-CFO/STO VAN with varying CFO nanopillar densities and BFO/CFO/STO bilayer were compared with that of the single layer BFO/STO and CFO/STO samples to delineate the possible coupling between the two materials. The in-plane M-T results of both BFO-CFO/STO VAN and BFO/CFO/STO bilayer, surprisingly, do not show obvious magnetic phase transitions like single layer BFO/STO. Nevertheless, it is noted that the FC and ZFC curves start to split at around 300 K, indicating that the ferromagnetism (FM) in CFO may have suppressed the anti-ferromagnetism (AFM) in BFO. The slope of the FC curves in BFO-CFO/STO VAN and bilayer BFO/CFO/STO exhibited similar behavior as that of pure CFO films, suggesting that in the in-plane orientation the CFO pillar may have percolated to form continuous paths. The in-plane M-H measurements performed at 20 K also suggests a strong magnetic coupling between CFO and BFO phase. Detailed analysis of the anisotropic exchange energy between the FM-AFM interfaces in both BFO–CFO/STO VAN and bilayer BFO/CFO/STO will be presented and discussed.

Keywords: Bilayer, Nanocomposite, Magnetic coupling, Temperature