The effects of ZnO underlayer on microstructural and magnetic properties of BaFe12O19 thin films

Barium ferrite films have been grown by pulsed laser deposition on oxidized Si (100) with and without ZnO buffer layers. The films grown directly on S iO2/Si exhibit a granular structure with two easy axes (in-plane and perpen dicular) and strong magnetic coupling. It was found that a ZnO underlayer p romotes the orientation of the c-axis perpendicular to the film plane. Addi tionally, good separation between the grains and a low exchange coupling ca n be achieved in BaFe12O19/ZnO/SiO2/Si films. Grain isolation and magnetic de-coupling are believed to be caused by the interdiffusion between the fil m and the ZnO buffer layer, which gives birth to a new non-magnetic phase ( ZnFe2O4).