Galvanomagnetic Effects in Magnesium Stannide Mg₂Sn

The weak field magnetoresistance coefficients and the Hall mobilities have been measured at temperatures between 77°K and 196°K on oriented single crystals of n - and p -type magnesium stannide having carrier concentrations ranging from 1.3×10 16 to 9×10 17 per cm 3 . The magnetoresistance coefficients of all n -type samples satisfy very well the symmetry relations appropriate for a <100> ellipsoid-of-revolution multivalley model of energy surfaces over the whole temperature range. The energy spheroids are prolate. The value of anisotropy parameter K =( m l / m t )·(τ t /τ l ) for the purest sample is 4.2 at 142°K and decreases to 3.5 as temperature decreases to 77°K, while for the impure samples the lower K values are obtained, indicating ionized impurity scattering effect. The same <100> symmetry relations seem to be held for p -type sample too at temperatures between 77°K and 169°K, although not conclusive. Anisotropy of hole band is, however, much less than that of the electron band. The value of K is about 1.7 or 0.6 if <100> spheroid model is taken. Existence of another spherical band might be possible.