An investigation of the resistivity anisotropy in nickel alloys

The electrical resistivity of nickel alloys, if extrapolated to B=0, depends on the angle between the current and the magnetization. The authors have measured, at 4.2K, this resistivity anisotropy for ternary alloys of general composition Ni 97 A 3-x B x , where A and B denote different metallic elements. These alloys include Ni(AlCr), Ni(AuCo), Ni(AuRh), Ni(CoRh), Ni(CoRu), Ni(CrFe), Ni(CrMn), Ni(CrSn), Ni(CrTi), Ni(CuRh), Ni(CuRu), Ni(CuV), Ni(FePt), Ni(FeRe), Ni(RhRu) and Ni(RuTi). The experimental results have been analyzed in terms of Mott's two current conduction model. In this model it is assumed that the conduction electrons of spin direction parallel or antiparallel to the magnetization contribute individually to the current. Each impurity element in nickel has got two residual resistivities, one for each spin current. These residual resistivities are derived for the ferromagnetic moment parallel and perpendicular to the current. It is found that the resistivity anisotropy is large for one of the spin currents (about +10%) while that for the other varies around -2%.