The magnetic properties of thin-film samples of MnBi0.8Al x with aluminum concentrations of x=0.0, 0.4, 0.6, and 0.8 were systematically studied over a temperature range of 20 to 300 K. The as-deposited films are amorphous and nonmagnetic, but highly textured polycrystalline films that are ferromagnetic are formed by annealing at 350°C. Our measurements show that the coercivity of such films rapidly decreases, then approaches a constant value (4 kOe for x=0.4) with increasing annealing time. Magnetic measurements show that both anisotropy and coercivity decrease with decreasing temperature. Unlike bulk MnBi, our MnBi0.8Alx thin films do not have a spin reorientation transition at low temperatures. This may be due to impediment of the lattice contraction by the Al atoms doped into the interstitial sites of the MnBi lattice.
ASJC Scopus subject areas
- Physics and Astronomy(all)