Methods of fabricating magnetic devices are described herein. Methods involve exposing a magnetic film, such as a CoFeB film, to a reducing agent before, during, or after depositing a metal oxide film using atomic layer deposition or chemical vapor deposition. Some methods include exposing the magnetic film in cycles involving exposure to a reducing agent, exposure to a magnesium-containing precursor, and exposure to an oxidant. Methods are suitable for depositing a magnesium oxide layer on a CoFeB layer to form part of a magnetic tunnel junction.