Cluster spin-glass behavior in Ni2In-type Mn-Cu-Ga alloys

We report the structural and magnetic properties of Ni2In-type (Mn0.25Cu0.25)(66)Ga-34 alloy by using powder X-ray diffraction, DC- and AC-susceptibility, aging effect and magnetic memory effect measurements. From the results of the DC-susceptibility measurements, an irreversible temperature Tirr(0) = 109.1 +/- 1.4 K and a crossover exponent Phi = 4.9 +/- 0.3 are obtained, which indicate that our system favors a canonical Heisenberg spin-glass state. From the AC-susceptibility results, the shift of freezing temperature with frequency is characterized by a medium Mydosh parameter of 0.03. Furthermore, a relaxation time of the spin flip tau(0) = 1.1 x 10(-9) s and a critical exponent zv = 7.5 are obtained by the fitting of power law. A significant aging effect and a magnetic memory effect in both zero-field-cooled and field-cooled protocols are observed. In addition, the memory effect existing in a negative T cycle but missing in a positive T cycle favors the hierarchical model in our sample. All the above observations render a cluster spin-glass behavior in (Mn0.25Cu0.25)(66)Ga-34 alloy. (C) 2019 Elsevier B.V. All rights reserved.