Isotropic magnetoresistance of icosahedral Al-Pd-Mn

The temperature dependence of the electrical resistivity rho(T) and the mag netoresistance Delta rho(B,T)/rho(0,T) have been studied along the twofold and fivefold symmetry directions of an icosahedral Al-Pd-Mn in a high quali ty monograin crystal. To control the influence of any magnetic contribution , samples from the transversal and axial extremes of the crystal were measu red along both the twofold and fivefold symmetry directions. The temperatur e dependence of the resistivity and the magnetoresistance were found to be isotropic. rho(T) and Delta rho(B,T)/rho(0,T) varied in a random way in the transversal direction of the ingot, while systematic variations were obser ved along the growth direction. These observations could be qualitatively c orrelated to a gradient of the Mn concentration of below 0.2%/cm in the gro wth direction of the crystal. [S0163-1829(99)10433-8].