Structural, magnetic and magneto-transport properties of Pt-alloyed MnBi thin films

The structural, magnetic and magneto-transport properties of highly c-axis oriented Mn(55-x)Pt(x)Bi(45) (x=0, 1.5, 3, and 4.5) thin films have been investigated. The coercivity of the Pt-alloyed thin films increases and the saturation magnetization decreases as the Pt concentration increases. The anisotropy field H(o) increases as a function of Pt concentration, too but the coercivity increases more rapidly than the anisotropy field. This indicates an enhanced domain-wall pinning, caused by increased interstitial disorder due to the occupancy of regular Mn sites by Pt. The same mechanism explains the reduced magnetization. All samples exhibit a large extraordinary Hall effect with anomalous Hall coefficient about an order of magnitude larger than the ordinary Hall coefficient. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3360204]