Faraday Rotation and Hysteresis Properties of Ferrite Thin Films

Abstract

Faraday rotation measurements on ferrimagnetic oxides have so far been limited to single crystals which are rendered transparent by grinding. In the present studies films of NiFe2O4 and CoFe2O4, of thickness 1000–8000 Å, suitable for optical studies are prepared by oxidizing films of the alloys NiFe2 and CoFe2 sputtered on silica substrates. The Faraday rotation is determined with the film magnetized along axes both normal and parallel to its surface. Using the latter arrangement, optical hysteresis loops are recorded and checked against those obtained with a vibrating sample magnetometer. The dependence of loop shape and coercive force on film thickness and oxidation temperature is studied.