Magnetic and electrical properties of amorphous CoFeB films

[[abstract]]CoFeB films were deposited on glass substrate by the sputtering method. From x-ray-diffraction and electron-diffraction-ring patterns, the major phase in the as-deposited CoFeB film is amorphous (or nanocrystalline). However, we could also identify a minor CoFe(110) crystalline phase in the film. We have tried to suppress this crystalline phase by changing the Ar partial pressure (PAr) during deposition and found that the optimal condition is PAr=5×10-3 Torr. Because the electrical resistivity value (ρ) of the film is in general larger than 100 μΩ cm, it also indicates that the amorphous phase is dominant. From the temperature coefficient of resistance measurement, we learn that the amorphous phase in the CoFeB film crystallizes in succession at two higher temperatures (Tcr1 and Tcr2) than the room temperature (RT). Besides the electrical properties, the film thickness (tf) dependence of saturation magnetization (Ms), saturation magnetostriction (λs), and coercivity (Hc) has also been discussed. From the Auger-depth profile analysis, it is found that there is one CoOx (with 0.4⩽x