Influence of ion irradiation on the magnetic properties of Fe/Cr multilayers

Influence of ion irradiation on the magnetic properties of Fe/Cr multilayers

The in uence of Ar-ion irradiation on the microstructure and magnetic properties of Fe/Cr multilayers is studied. An increase in the interface roughness of Fe/Cr multilayers, caused by irradiation with 200 keV Ar ions whose dose exceeds 5 1012 Ar/cm2, is clearly seen by conversion electron Mossbauer spectroscopy (CEMS). This modication of the microstructure induces distinct changes in the magnetization reversal (an increase in remanence magnetization and a decrease in saturation eld), and greatly reduces the giant magnetoresistance (GMR) eect on increasing the irradiation dose. An enhanced immunity of the GMR eect to the ion irradiation on increasing the thickness of Cr layers, as well as correlation between the changes of GMR and the antiferromagnetically coupled fraction, suggests that the main eect responsible for the decrease in GMR is the formation of pinholes. The temperature dependence of remanence magnetization conrms increases in pinhole density and size during implantation. However, for doses exceeding 2 1013 Ar/cm2, volume intermixing seems to be a dominant mechanism responsible for the further degradation of GMR and the antiferromagnetic interlayer exchange coupling.

The in uence of Ar-ion irradiation on the microstructure and magnetic properties of Fe/Cr multilayers is studied. An increase in the interface roughness of Fe/Cr multilayers, caused by irradiation with 200 keV Ar ions whose dose exceeds 5 1012 Ar/cm2, is clearly seen by conversion electron Mossbauer spectroscopy (CEMS). This modication of the microstructure induces distinct changes in the magnetization reversal (an increase in remanence magnetization and a decrease in saturation eld), and greatly reduces the giant magnetoresistance (GMR) eect on increasing the irradiation dose. An enhanced immunity of the GMR eect to the ion irradiation on increasing the thickness of Cr layers, as well as correlation between the changes of GMR and the antiferromagnetically coupled fraction, suggests that the main eect responsible for the decrease in GMR is the formation of pinholes. The temperature dependence of remanence magnetization conrms increases in pinhole density and size during implantation. However, for doses exceeding 2 1013 Ar/cm2, volume intermixing seems to be a dominant mechanism responsible for the further degradation of GMR and the antiferromagnetic interlayer exchange coupling.