Spin-glass-like behavior and related properties of aluminum-based AI-Y-RE-Ni (RE=Gd, Dy) amorphous alloys

摘要

Magnetic properties of the following alloys: Al_(87)Y_5Ni_8, Al_(87)Y_4Gd_1Ni_8, Al_(87)Gd_5Ni_8, Al_(87)Y_4Dy_1Ni_8, and Al_(87)Dy_5Ni_8 were studied by means of magnetic, electrical transport, and heat capacity measurements. Low temperature isotherms, magnetization versus magnetic field, were analyzed numerically to obtain distribution of magnetic moments in the interacting clusters system. The resistivity p_r(T) and specific heat C(T)/T data indicate a spin-glass-like magnetic state for the alloys with RE=Gd or Dy. The obtained distribution of magnetic moments reveals the presence of small clusters of Ni separated by magnetic RE/Ni regions which exhibit a frustration. We found that in the Al_(87)Y_5Ni_8 alloy, Ni atoms form only two types of magnetic clusters with about 70 or 300 atoms. Doping of the based system by RE atoms leads to a reduction of Ni clusters magnetic moment via breaking off Ni-Ni ferromagnetic interaction within the cluster. We also found that resistivity ρ_r(T) of the investigated amorphous alloys Al-Y-RE-Ni is almost T-independent between 200 and 300 K which is a result of strong atomic and magnetic disorder.