Examination of the critical behavior and magnetocaloric effect of the ferromagnetic Gd-Au-Si quasicrystal approximants

We investigate the critical behavior and magnetocaloric effects of Gd-Au-Si (GAS) ferromagnetic quasicrystal approximants, ${\mathrm{Gd}}_{13.7}{\mathrm{Au}}_{72.7}{\mathrm{Si}}_{13.6}$ [referred to as GAS(0)] ${\mathrm{Gd}}_{15.4}{\mathrm{Au}}_{68.6}{\mathrm{Si}}_{16.0}$ [GAS(100)]. The former is a conventional Tsai-type 1/1 approximant crystal, while latter has slightly different atomic decoration from Tsai type (thus referred ``pseudo-Tsai'' type). Their exponents at transitions are close those mean-field theory. Both GAS systems exhibit an interesting magnetic-field dependence specific heat, which reflected in their effect (MCE). MCE characterized by adiabatic cooling (heating) over relatively broad temperature range below $\ensuremath{\sim}30$ K, stems feature heat.