High Perpendicular Magnetic Anisotropy of Electrodeposited Co-Pt Films

Abstract

Co-Pt alloy thin lms were galvanostatically electrodeposited from an aqueous electrolyte consisting of Co sulphamate and PtP salt. A 30-nm-thick Ru bu er layer was used to enhance the perpendicular magnetic anisotropy. The Co-Pt thin lms on a Ru bu er layer exhibited high perpendicular magnetic anisotropy. They also exhibited a as high out-of-plane coercivity and a high squareness of up to 6414 Oe and 0.86, respectively, without any heat treatment. The intrinsic perpendicular magnetic anisotropy constant, Ku, of the Co-Pt alloy obtained using a torque magnetometer was 8.3 106 erg/cm3. The composition of the electrodeposited Co-Pt alloy was Co-25.19 at.% Pt corresponding to the Co3Pt phase. According to the transmission electron microscopy (TEM) analysis, the out-of-plane coercivity and squareness increased signi cantly due to the growth of physically isolated columnar grains with the c-axis perpendicular to the lm plane.