Effect of the pH of solutions on the coercivity and microstructure of chemically deposited CoP cilms

Specific features of the variation in the microstructure and coercivity $H_C$ of chemically deposited CoP films with the pH of the solutions are determined. It is established that around pH $\sim$ 8.5, the film undergoes the structural transition from the submicrocrystalline to nanocrystalline state, which is followed by the transition from the crystalline to amorphous phase. It is demonstrated that the observed transition is not accompanied by the change in the crystallographic structure and is caused by a decrease in the geometrical sizes due to embedding of P atoms. It is found that the CoP films fabricated at pH $\sim$ 8.5 have the properties characteristic of compact nanocrystalline materials.