Anisotropic magnetism and resistivity of an Al70Ni15Co15 decagonal quasicrystal

We report the results of dc magnetization and electrical resistivity studies of a single-domain Al70Ni15Co15 decagonal quasicrystal. The temperature dependence and anisotropy of the electrical resistivity are in excellent agreement with previous results for a similar sample. The magnetic properties were determined by superconducting quantum interference device magnetometry over the temperature range 1.8–300 K for magnetic fields between 10 Oe and 10 kOe. The magnetic behavior can be characterized by a weak ferromagnetic component M0(H) which saturates in moderate fields (H≊1 kOe) and a differential susceptibility, χ0=ΔM/ΔH, obtainable from the high-field data. The observed magnetization M=χ0H+M0 is slightly anisotropic and essentially temperature independent below room temperature. For H parallel to the quasicrystal axis, we observe χ0∥=7.1×10−7 emu/g and M0∥=2.0×10−3 emu/g. For H perpendicular to the quasicrystal axes, we obtain χ0⊥=8.2×10−7 emu/g and M0⊥=1.7×10−3 emu/g. An anisotropic and weak superconducting transition was observed at T=3.2 K, corresponding to a superconducting volume fraction of only ∼10−3.