Growth of iron, nickel, and permalloy thin films by MOCVD for use in magnetoresistive sensors

Thin films of elemental iron and nickel, plus a wide composition range of iron-nickel alloys, have been deposited by atmospheric pressure metal organic chemical vapor deposition at a growth temperature of 200 degrees C, using iron pentacarbonyl and nickel tetracarbonyl as the source precursors. Detailed magnetoresistance measurements of the permalloy layers showed that the maximum value of magnetoresistance occurred at a composition of approximately 90 % Ni10 % Fe, and the maximum sensitivity occurred at approximately 80 % Ni20 % Fe, in accordance with literature values. In addition, both the application of an 80 mT magnetic field during deposition and the annealing of samples at temperatures higher than the growth temperature of 200 degrees C improved the magnetic properties.