Search

The ternary alloy Ag–In–Ce is the only Ce-based quasicrystal approximant showing the heavy fermion feature. Here, we report the physical properties of Ag–In–(CexY1−x). As the Ce concentration x is diluted by the nonmagnetic element Y, the spin glass freezing temperature Tf is progressively suppressed. At T > Tf, the uniform magnetic susceptibility and electronic specific heat coefficient show \(\chi (T,x)^{ - 1} = \alpha [T^{\zeta } + \theta _{\text{eff}}^{\zeta }(x)]\) (where α is a constant, ζ \(\simeq \) 0.7, and θeff is an effective Weiss temperature) and \(C(T,x)/T = \beta \ln [T/T_{0}(x)]\) (where β is a constant and T0 is a characteristic temperature), respectively. Near the critical concentration xc where θeff vanishes, χ and C/T exhibit power-law and logarithmic divergence, respectively, as T → 0. We stress that α, ζ, and β are independent of x, indicating that the Tζ and ln T terms come from local fluctuations that are present everywhere in the x–T phase diagram, regardless of quantum critical point. We argue that the quantum critical behavior is driven by valence fluctuations. [ABSTRACT FROM AUTHOR]

The Ag–In–Ce alloy is an approximant crystal to a Tsai-type quasicrystal and exhibits heavy-fermion (Kondo) physics. This new type of Kondo material exhibits spin-glass ordering below the freezing temperature Tf ∼ 0.3 K at ambient pressure. Here we investigated the effect of hydrostatic pressure on the Ag–In–Ce alloy. Spin-glass features, such as the frequency-dependent cusp near Tf in the ac magnetic susceptibility curve, were observed even under external pressure. In addition, the C/T value (where C is the specific heat) increased with decreasing temperature and exhibited a broad peak above Tf. The Tf increased as the pressure increased up to its highest value in the experiment (approximately 2.6 GPa). [ABSTRACT FROM AUTHOR]