Interface shape and concentration distribution in crystallization from solution under microgravity

The Kerr rotation of MnBixAl0.5(0.4 less than or equal to x 0.9) thin films with and Al protective layer as a function of the Bi concentration, x, has been investigated. Compared with MnBix thin films, it is found that a large enhancement of Kerr rotation appears in the MnBixAl0.15 thin films with 0.4 less than or equal to x less than or equal to 0.7, but no enhancement of Kerr rotation appears when x is greater than 0.7. When x = 0.5, a maximum Kerr rotation of 2.75 degrees is observed at 633 nm for the MnBi0.5Al0.15 thin film, which is much larger than that of 1.56 degrees for the MnBi0.5 thin film. For the MnBixAl0.15 thin films with 0.4 less than or equal to x less than or equal to 0.7, the c lattice shrinking may result in a stronger hybridization between Bi 6p and Mn 3d states, which also should be responsible for the large enhancement of Kerr rotation. In addition, the saturation magnetization M-s is reduced from 4 x 10(5) A/m for the MnBi0.5Al0.15 thin film to 3 x 10(5) A/m for the MnBi0.5Al0.15 thin film, suggesting that some of Al may also substitute for Mn at the octahedrtal sites.