Specific Heat Study of Magnetic and Superconducting Transitions in CePt3Si

TL;DR

This study investigates the specific heat and resistivity of CePt3Si, revealing coexistence of antiferromagnetism and two distinct superconducting phases at different transition temperatures.

Contribution

It provides detailed measurements showing the coexistence of antiferromagnetic order with two separate superconducting transitions in CePt3Si.

Findings

Antiferromagnetic transition at 2.2 K observed in all samples.

Two superconducting transitions at ~0.45 K and ~0.75 K.

Systematic relation between magnetic and superconducting transitions.

Abstract

Measurements of specific heat between 80 mK to 4 K and electrical resistivity between 80 mK to 10 K were carried out for polycrystalline CePt3Si samples cut into small pieces (typically $\sim $10 mg). In the specific heat measurements, we observed an antiferromagnetic transition jump at TN = 2.2 K for all the samples, while the heights have large variations. As regards superconductivity, we observed two distinct transition jumps at Tcl $\sim$ 0.45 K and Tch $\sim$ 0.75 K, which were the same for all the samples. From the measurements of specific heat and resistivity, systematic relations were found between antiferromagnetic and superconducting transitions. We conclude that antiferromagnetism, whose transition temperature is 2.2 K, coexists with superconductivity, whose transition temperature is Tcl. In this sample, residual electronic specific heat coefficient in the superconducting state $\gamma_{\rm s}$ was quite small, and specific heat divided by temperature below Tcl decreased almost linearly with decreasing temperature. In order to reveal the characteristic properties of the magnetism and superconductivity of the CePt3Si system, it is important to study the two superconducting phases with Tcl and Tch, respectively.