Growth behavior and magnetic property of electroless NiCoFeP films

The electroless NiCoFeP films were deposited on a silicon substrate in a bath containing Ni2+, Co2+, and Fe2+ ions with a concentration ratio of 1:1.9:1.2. These films were characterized by using transmission electron microscope, energy dispersive X-ray spectrometer, and alternating gradient magnetometer for their microstructure, crystal structure, and magnetic properties. The result showed that the film deposited at the initial stage (about 10 s) consists of only one phase with a crystal structure of FCC Ni and a composition about Ni (69 at%), Co (19 at%), Fe (4 at%), and P (7 at%); The film deposited at the latter stage (about 30 s) consists of two phase, one is similar to that of initial stage and the other has crystal structure of HCP Co with a composition about Ni (35 at%), Co (44 at%), Fe (19 at%), and P (2 at%). The saturation magnetization and coercivity of electroless NiCoFeP films vary from 525 to 1546 emu/cm3 [0.68-2.01 T] and from 51.44 to 88.5 Oe [4.09-7.04 kA/m], respectively.

► The electroless NiCoFeP films are deposited on Si substrate in a plating bath with pH value of 9. ► At the initial stage (about 10 s) in the plating process, the film contains only Ni-rich phase. ► At the latter stage (about 30 s), the film contains Ni-rich phase and Co-rich phase. ► The Ms and Hc of electroless NiCoFeP films varied from 525 to 1546 emu/cm3 and from 51.4 to 88.5 Oe, respectively.