MAGNETIC AND MAGNETO-OPTICAL PROPERTIES OF THE MnBi THIN FILMS DOPED WITH Nd

In this paper the structure, magnetic and magneto-optical properties of the Nd-doped MnBi thin films are discussed. The analyses by the Auger profile and X-ray diffraction of these films show that the crystal structure composed mainly of MnBi hop is formed after suitable annealing, and the structure of MnBiNd alloy which is much similar to the MnBi may be existed for the MnBi films doped with Nd. According to the crystal structure with NiAs type the lattice constants of MnBiNd alloy are calculated: a = 4.14?, c = 5.80?. The torque curve and the hysteresis loop show that the film possesses perpendicular anisotropy. When the ratio of raw materials Mn/Bi is two or so, we can obtain the suitable σs, the proper Hc(1-4 kOe), and a very large Kerr rotation angle θK (1.5-2°). The magneto-optical profile shows that the frequency corresponding to the maximum θK shifts to low frequency as Nd component increases .It was found that the grain size of all films which were deposited on the cooled glass substrates is limited in the range of 200 to 400?, moreover, the high temperature phase transition of MnBi alloy was avoided by Nd doping.