Smart nanocomposite SrFe12O19/α or γ - Fe2O3 thin films with adaptive magnetic properties

Ferromagnetic (FM)/antiferromagnetic (AFM) or hard-FM/soft-FM nanocomposites are compelling due to their benefits in future spintronics. We fabricated two distinct nanocomposites thin films by altering the gaseous environment during laser ablation of SrFe12O19: one in a vacuum (FM/AFM: SrFe12O19/alpha-Fe2O3) and other in an oxygen atmosphere (hard-FM/soft-FM: SrFe12O19/gamma-Fe2O3). The in-situ growth and ex-situ annealing temperatures significantly affect the composition of AFM, soft-FM, and hard-FM phases in nanocomposite films. M-H loops show substantial coercivity values (similar to 5 kOe) in room temperature grown FM/AFM nanocomposites films, while hard-FM/soft-FM nanocomposites films display an exchange spring system with hard (5.8 kOe) and soft (0.16 kOe) magnetic phases. Morin transition of AFM alpha-Fe2O3 phase is shifted to a lower temperature of around 60 K compared to the bulk value of 260 K, owing to intergranular strain effect, and this has a detrimental effect on FM properties of FM/AFM nanocomposite films. Despite most research focuses on multilayers, the aforementioned unique magnetic properties in FM/AFM and hard-FM/soft-FM nanocomposites thin films hold significant relevance for numerous applications.

Automated summary

The unique magnetic properties of FM/AFM and hard-FM/soft-FM nanocomposite thin films have significant relevance for numerous applications. The composition and performance of different magnetic phases in the nanocomposite films can be significantly affected by the laser ablation conditions and annealing temperature.