Composition dependence of magnetization of ion implanted cobalt layers

Ion implantation of P+ or Si+ ions in Co layers sputtered or vapour deposited on SiO2 substrates is carried out to produce Co1-xPx and Co1-xSix alloys with 0 ≤ x ≤ 0.4. The magnetic moment per Co atom nB is determined by measuring the magnetic moment MSV of the layer volume V with a torque magnetometer. Rutherford Backscattering Spectrometry (RBS) is used for determination of both, the number of Co atoms per area (Nd)Co and the metalloid content in the layer. A linear decrease of nB with increasing phosphorus or silicon content is obtained. The slope of the lines is compared with known theoretical models, e.g. with the rigid band model, the valence bond model, and with the assumption that a nonmagnetic compound like Co2P or Co2Si is formed, and with results achieved on electrodeposited Co-P and Co-Si alloys. (author)