Growth of M-type hexaferrite thin films with conical magnetic structure

Thin films of the M-type hexaferrite, BaFe10.2Sc1.8O19, have been grown on Al2O3 (00.1) substrates by pulsed laser deposition. Post-deposition annealing improves the structural quality and produces completely relaxed thin films. The post-annealed films show magnetic behavior corresponding to a conical magnetic structure, which is required to establish the magnetoelectric effect in hexaferrites. The magnetic phase diagram has been obtained from hard magnetization curves. Finite-size effects due to the restricted length scale of the magnetic helix explain differences in magnetic properties between thin films and the bulk.