Scanning Microwave Microscopy Characterization of Spin-Spray-Deposited Ferrite/Nonmagnetic Films

Abstract

In this study, we performed single-grain-boundary characterization of ferrite films at radio and microwave frequencies using scanning microwave microscopy (SMM). The sample consisted of Fe 3 O 4 /photoresist/Fe 3 O 4 multilayers deposited on glass substrate at 90°C by spin-spray coating. SMM images were recorded at various resonant frequencies between 2.0 GHz and 8.0 GHz. These images showed higher electrical conductivity at grain boundaries than at the core of grains. This phenomenon can be explained by space-charge accumulation at the grain boundary.