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

Abstract

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 3 nm 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 tAu. 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.