Structure, magnetic and magneto-optical properties of MnBiRE thin films

The crystal structure, magnetic and magneto-optical properties for RE doped MnBi thin films (RE = Ce, Pr, Nd and Sm) are reported. The X-ray diffraction spectra show that the structure of MnBiRE is the mainly MnBi hcp phase mixed with a small part of MnBiRE hcp phase. The magneto-optical spectra show that doping with an RE element into MnBi film can strongly enhance the Kerr rotation angle θK in the range of RE concentration x = 0.02–0.25 and the figure of merit is about 1.5 at λ = 633 nm and room temperature. The magnetization is 20–40 emu/g, Hc = 1–4 kOe, Ku = 5 X 106 erg/cm3, Tc = 360°C which is mainly independent of small contents of doped RE element. The reason of the large enhancement of the Kerr rotation angle about 2–2.5° at x = 0.02–0.25 for MnBiRE films for RE = Ce, Pr and Sm is discussed based on the electron transition between 3d–6p bands of MnBi alloy.