Study of [Co/Ni]N/[Co/Pt]N-based spin valves with perpendicular magnetic anisotropy

A structure of Pt/ [Co/Ni](2)/Au/ [Co/Pt](N) with perpendicular magnetic anisotropy was prepared successfully by magnetron sputtering technique. The magnetic properties dependence of Au thicknesses and [Co/Pt] layer repetition number have been studied. The results show that when the [Co/Pt] layer repetition number is 4, the strongest coupling among the samples occurs when the Au layer is 3nm for its largest Hall voltage and large switching field plateau. The Hall loop of the sample has obvious perpendicular magnetic anisotropy. The magnetoresistance of Pt/ [Co/Ni](2)/Au(t)/ [Co/Pt](4) has vibration behaviour due to the Ruderman-Kittel-Kasuya-Yosida interaction with the increase of t(Au). As the thickness of the Au spacer is determined to be 3 nm, the study of dependence of [Co/Pt] layer repetition number to the magnetic properties shows that the N has significant influence to the magnetoresistance of the multilayer films. When N is 5, the MR of the sample has the maximum value and the optimum sample is structured as Pt(4)/[Co(0.2)/Ni(0.4)](2)/Co(0.2)/Au(3)/[Co(0.4)/Pt(2.0)](5)/Pt(0.5) (unit:nm). It has obvious perpendicular magnetic anisotropy features and large switching field plateau and the integration with device can be studied furtherly.