CePdAl with Ce $4f$ moments forming a distorted kagome 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 Grüneisen parameter, ${\mathrm{<ruby><rb>\Gamma </rb><rt>がんま</rt></ruby>}}_{\mathrm{mag}}$, on single crystals of ${\mathrm{CePd}}_{1-x}{\mathrm{Ni}}_x\mathrm{Al}$ with $x\le 0.16$ at temperatures down to 0.05 K and magnetic fields $B$ up to $8\mathrm{T}$. 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 AF quantum criticality of Hertz-Millis-Moriya type arises for $x=0.05$ and $x=0.1$ at the suppression of three-dimensional magnetic order. Furthermore, ${\mathrm{<ruby><rb>\Gamma </rb><rt>がんま</rt></ruby>}}_{\mathrm{mag}}\left(B\right)$ shows an additional contribution near $2.5\mathrm{T}$ for all concentrations, which is ascribed to correlations of the frustrated one-third of Ce moments.

• Received 22 August 2016
• Revised 7 December 2016

DOI:https://doi.org/10.1103/PhysRevB.94.220405