Signature of frustrated moments in quantum critical CePd$_{1-x}$Ni$_x$Al
  CePdAl with Ce $4f$ moments forming a distorted kagom\'e network is one of the scarce materials exhibiting Kondo physics and magnetic frustration simultaneously. As a result, antiferromagnetic (AF) order setting in at $T_{\mathrm{N}} = 2.7$~K encompasses only two thirds of the Ce moments. We report measurements of the specific heat, $C$, and the magnetic Gr\"uneisen parameter, $\Gamma_{\rm mag}$, on single crystals of CePd$_{1-x}$Ni$_x$Al with $x\leq 0.16$ at temperatures down to 0.05~K and magnetic fields $B$ up to $8$~T. Field-induced quantum criticality for various concentrations is observed with the critical field decreasing to zero at $x_c\approx 0.15$. Remarkably, two-dimensional (2D) AF quantum criticality of Hertz-Millis-Moriya type arises for $x=0.05$ and $x=0.1$ at the suppression of 3D magnetic order. Furthermore, $\Gamma_{\rm mag}(B)$ shows an additional contribution near $2.5$~T for all concentrations which is ascribed to correlations of the frustrated one third of Ce moments. 
Akito Sakai, Stefan Lucas, Philipp Gegenwart, Oliver Stockert, Hilbert   v. L\"ohneysen, and Veronika Fritsch
cond-mat.str-el