Figure 1

Electronic contribution to the specific heat, $C_{\mathrm{el}}(T)/T$, of ${\mathrm{CePt}}_4{\mathrm{Ge}}_{12-x}{\mathrm{Sb}}_x$ for different $x$. The low-$T$ nuclear Schottky contribution to $C_p(T)$ has been subtracted. Inset: $C_{\mathrm{el}}(T)/T$ of ${\mathrm{CePt}}_4{\mathrm{Ge}}_{11}\mathrm{Sb}$ in different magnetic fields. At $B=0$, $C_{\mathrm{el}}(T)/T$ exhibits a logarithmic increase toward the lowest temperatures (indicated by the line), while $C_{\mathrm{el}}(T)/T$ becomes constant in external magnetic fields.Reuse & Permissions

Figure 2

(a) Normalized resistivity $\rho (T)/{\rho }_{300\mathrm{K}}$ of ${\mathrm{CePt}}_4{\mathrm{Ge}}_{12-x}{\mathrm{Sb}}_x$ for different $x$ on a logarithmic temperature scale. (b) Magnification for $x=1.9$, 2.5, and 3. Straight lines indicate a logarithmic dependence of $\rho (T)/{\rho }_{300\mathrm{K}}$ on $T$, reminiscent of incoherent Kondo scattering. The maximum and the kink in $\rho (T)/{\rho }_{300\mathrm{K}}$ at $T_{\max }$ and at the Néel transition, $T_N$, respectively, are marked by arrows. (c)–(e) Low-temperature resistivity $\rho (T)$ for $x=0$, 0.5, and 1. Except for $x=0$, $\rho (T)$ increases toward low $T$. In (e), the dashed line marks a logarithmic and the dotted line a linear temperature dependence of $\rho (T)$. In addition to 0 T (circles), data in magnetic fields of 1 T, 3 T, 5 T, and 9 T (solid lines), are shown.Reuse & Permissions

Figure 3

(a) Density of states (DOS) at the Fermi energy ($E_F$) as a function of the Sb concentration $x$ calculated by different techniques and/or with different assumptions, as indicated. (b) Experimental lattice parameter $a(x)$ of ${\mathrm{CePt}}_4{\mathrm{Ge}}_{1-x}{\mathrm{Sb}}_x$. (c) Temperature–unit-cell volume ($T\mathrm{\text{−}}V$) phase diagram of ${\mathrm{CePt}}_4{\mathrm{Ge}}_{12-x}{\mathrm{Sb}}_x$. The corresponding Sb concentration is indicated on the top axis. Samples $x=0$ and 0.5 exhibit LFL behavior in an extended temperature range. The AFM ordering temperature $T_N$ determined from specific heat is represented by diamonds, and that determined from resistivity data is represented by squares. The temperature of the maximum in the resistivity $\rho (T)$, $T_{\max }$, is represented by stars. The samples with $x=1$ and 1.3 show NFL behavior at low $T$. ${\mathrm{CePt}}_4{\mathrm{Ge}}_{10.5}{\mathrm{Sb}}_{1.5}$ and ${\mathrm{CePt}}_4{\mathrm{Ge}}_{10.1}{\mathrm{Sb}}_{1.9}$ both display LFL behavior below $T_{\mathrm{LFL}}$ (circle). The latter compound orders AFM, while ${\mathrm{CePt}}_4{\mathrm{Ge}}_{10.5}{\mathrm{Sb}}_{1.5}$ does not show any magnetic order. The regions where LFL and NFL behaviors are observed are indicated.Reuse & Permissions