ANISOTROPIC MAGNETISM AND RESISTIVITY OF AN AL70NI15CO15 DECAGONAL QUASI-CRYSTAL

We report the results of de magnetization and electrical resistivity s tudies of a single-domain Al70Ni15Co15 decagonal quasicrystal. The tem perature dependence and anisotropy of the electrical resistivity are i n excellent agreement with previous results for a similar sample. The magnetic properties were determined by superconducting quantum interfe rence device magnetometry over the temperature range 1.8-300 K for mag netic fields between 10 Oe and 10 kOe. The magnetic behavior can be ch aracterized by a weak ferromagnetic component M(0)(H) which saturates in moderate fields (H approximate to 1 kOe) and a differential suscept ibility, chi(0)=Delta M/Delta H, obtainable from the high-field data. The observed magnetization M=chi(0)H+M(0) is slightly anisotropic and essentially temperature independent below room temperature. For H para llel to the quasicrystal axis, we observe (chi 0 parallel to)=7.1x10(- 7) emu/g and M(0 parallel to)=2.0X10(-3) emu/g. For H perpendicular to the quasicrystal axes, we obtain (chi 0 perpendicular to)=8.2X10(-7) emu/g and M(0 perpendicular to)=1.7X10(-3) emu/g. An anisotropic and w eak superconducting transition was observed at T=3.2 K, corresponding to a superconducting volume fraction of only similar to 10(-3).