Magnetic and transport properties of alternately deposited Co-Bi films

Co-Bi films have been prepared on glass substrates by alternate electron-beam evaporation, and their magnetic and transport properties have been studied as a function of Co volume fraction x (vol %). When x increases, saturation magnetization increases linearly, while coercivity and resistivity decrease. The temperature dependence of resistivity is very weak. Both ordinary magnetoresistance (OMR) and anisotropic magnetoresistance (AMR) are observed. The OMR component, for which the Bi matrix is responsible, decreases with increasing x, while the AMR component, due to Co, increases. For x=17, the spontaneous Hall resistivity indicates strong temperature dependence. With the increase of temperature, polarity switches at 150 K from negative to positive. At room temperature, Hall resistivity exhibits a value as high as ∼1.6 μΩ cm or, in other words, a Hall coefficient of 5.25x10-10 Ω cm/G, which is larger than pure Co bulk by two orders of magnitude