Because of their importance to the development of magnetoresistive recording heads, the thickness dependence of the magnetoresistive properties of thin R.F. sputtered Permalloy films has been measured in the thickness range from 220Å to 5490Å. It was found that the

exhibits an oscillatory dependence on film thickness when saturated in a magnetic field. The resistivity ρ and Δρ/ρ also exhibit tendencies in this regard to a lesser degree. The primary source of this oscillatory thickness dependence is the exsistence of a quantum size effect [7] modified by the magnetic quantization producing a Landau level spectrum.[1]