Influence of buffer layers on the anisotropic magnetoresistance of NiCo films

NiCo films were deposited on NiFeCr and Ta buffer layers by using a DC magnetron sputtering system on Si substrates respectively. After deposition the samples were annealed at different temperatures. The structural and magnetic properties were systematically studied. It is shown that the value of anisotropic magnetoresistance (AMR) of the film with a NiFeCr buffer layer is higher than that of the film with a Ta buffer layer. XRD results indicate that the average grain size of the sample with a NiFeCr buffer layer is larger than that of the sample with a Ta buffer layer, and the situation of the NiCo/NiFeCr interface is different from that of NiCo/Ta. These would be responsible for the difference in AMR between the two kinds of films. A suitable anneal treatment is good for the films.