CRYSTALLOGRAPHIC AND MAGNETIC INVESTIGATIONS OF THE COBALT COLUMNS ELECTRODEPOSITED IN THE PORES OF ANODIC ALUMINA

Textured polycrystalline cobalt columns are electrochemically deposite d in the pores of anodic alumina layers of 15 mu m thickness. X-ray di ffraction investigations show that the cobalt columns are polycrystall ine and textured. The crystallite size of the cobalt columns is about 80 nm and the c axis is oriented at an angle of about 60 degrees towar ds the layer surface. The layers show perpendicular magnetization anis otropy. Anomalies in the magnetization parameters such as saturation m agnetization, coercivity and the area of the magnetization hysteresis loop around an angle of 40 degrees are also observed. Maximum coercivi ty of 1.40 kO(c) and a M(r)/M(s) ratio of 0.714 are observed for the m echanically polished AlMg1 substrate before anodic oxidation. The crys tallographic and magnetic data further suggest a possibility that perp endicular magnetic anisotropy of the layers is caused by the cobalt co lumns perpendicular to the layer surface rather than c-axis orientatio n of polycrystalline cobalt columns.