Structure and magnetization processes are investigated on MnBi thin films prepared by Chen's method, with a variety of evaporation atomic ratios and thicknesses. With an atomic ratio of Bi/Mn more than 1, we obtain a discontinuous film, where MnBi grains are separated by unreacted Bi, while for a ratio of less than 1, we obtain a continuous film the top surface of which is covered with excess Mn. Both kinds of films have an equally excellent alignment of the c axes. The former is very hard magnetically and its coercivity increases rapidly with the quantity of remaining Bi. However, the latter possesses a constricted hysteresis loop, with small coercivity, and consists of stripe domains, like bubble device materials. The thickness dependence of the magnetic properties are discussed. Finally an application of the continuous film as a magnetic field sensor is proposed.
ASJC Scopus subject areas
- Physics and Astronomy(all)