Magnetoresistance in FeSi films grown by molecular beam epitaxy

We have used molecular beam epitaxy apparatus to grow Fe-Si films. The films were grown by first depositing a nominal 40 Å of Fe, then a nominal thickness of Si, then a further nominal 40 Å of Fe. A plot of the ratio (remanent magnetisation/saturation magnetization) versus nominal Si layer thickness shows a minimum for a nominal thickness of 25 Å, and a plot of saturation field versus nominal Si thickness has a maximum for a nominal thickness of 20 Å. We find a room temperature magnetoresistance of more than 2% in films with nominal Si layer thicknesses of 20 Å. Raising the temperature causes a decrease in (remanent magnetization/saturation magnetisation) for films with nominal Si thicknesses of 20 Å and 25 Å.