Magnetic properties of multilayered Fe/Cu film deposited by facing targets sputtering (abstract)

Abstract

Iron and copper both form solid solutions with only a few atomic percent in ultimate concentration. Thus, multilayered films of ferromagnetic Fe and diamagnetic Cu provide unique means for investing the magnetic interaction among Fe thin layers distinctly separated by Cu layers and the role of Fe/Cu interface. Facing targets sputtering (FTS) apparatus has been developed for preparing multilayered films composed of very thin continuous layers of different metals with high mobility adatoms and low energy bombarding particles. Multilayered Fe/Cu films have been prepared on glass slide substrates by depositing alternatively Fe and Cu layers with 99.99% in purity using FTS apparatus. The thickness of individual Fe and Cu layers is in the range of 5–70 Å. Small-angle x-ray diffractometry indicates that the multilayered structure is formed even for each layer as thin as 5 Å. Saturation magnetization 4πMs of the Fe layer as thin as about 7 Å is comparable to that of bulk Fe. However, 4πMs of the films with an Fe layer thinner than 7 Å is remarkably small than that of the films with the thicker Fe layer. Coercivity Hc monotonously decreases with decreasing thicknesses of Fe and Cu layers from 70 Å to about 10 Å. The hysteresis M-H loop of the multilayered films with Fe layers thinner than 10 Å shows rotatable anisotropy, impling perpendicular anisotropy. When the thickness of the Fe layer is fixed at 13 Å, perpendicular anisotropy increases with decreasing the thickness of the Cu layer in the range below 13 Å. Heat treatments of the multilayered films up to 300 °C resulted in a change of layer structure and also magnetic properties. Dependence in magnetic properties and multilayered structures on annealing temperature will be discussed in detail.