Transport and calorimetry study of 20% La-doped CeIn3.

CeIn3, a prototypical antiferromagnet, is an ideal candidate for investigating the relationship between magnetism and superconductivity, as superconductivity is induced as the magnetic transition temperature (TN) is lowered to 0 K by applying pressure. When La is substituted for Ce,TNof CeIn3decreases to 0 K owing to the Ce dilution effects, thereby providing an alternative route to the zero-temperature quantum phase transition. In this study, we report a combinatorial approach to gain access to the critical point by applying external pressure to 20% La-doped CeIn3. Electrical resistivity measurements of La0.2Ce0.8In3show that theTNof 8.4 K at 1 bar is gradually suppressed under pressure and can be extrapolated to 0 K at approximately 2.47 GPa, thereby showing a similar pressure dependence ofTNas shown by undoped CeIn3. The kink-like feature in resistivity atTNof CeIn3changed to an obvious jump in the doped compound for pressures higher than 1.64 GPa, indicating depletion in the carrier density due to a gap opening. AC calorimetry measurements under applied pressure show that the size of the specific heat jump atTNdecreases with increasing pressure, but any signatures associated with the gap opening are not obvious, suggesting that the pressure-induced kink-to-jump change atTNin the resistivity is not a phase transition, but rather a gradual crossover. The low-temperature specific heat divided by temperature,C/T, does not strongly diverge with decreasing temperature, but is almost saturated near the projected quantum critical point, which can be attributed to a weak enhancement in the effective mass up to 2.6 GPa.