Electrical resistivity and magnetization measurements on the heavy fermion superconductor PrOs4Sb12

TL;DR

This study investigates the electrical resistivity and magnetization of the heavy fermion superconductor PrOs4Sb12, revealing detailed phase boundaries, critical fields, and evidence of a high field ordered phase potentially linked to quadrupolar ordering.

Contribution

It provides new experimental data on the phase diagram and magnetic properties of PrOs4Sb12, highlighting the high field ordered phase and its possible origins.

Findings

Identification of a high field ordered phase above 4.5 T

Detailed phase boundary of the high field phase

Determination of lower critical field Hc1 and peak effect onset

Abstract

The filled skutterudite compound PrOs4Sb12, the first example of a Pr-based heavy fermion superconductor, displays superconductivity with $T_c\sim 1.85$ K and has an effective mass $m^* \sim$ {50 $m_e$}, where $m_e$ is the free electron mass. For magnetic fields above 4.5 T, sharp features in the normal state electrical resistivity, magnetization, specific heat, and thermal expansion data suggest the occurrence of a phase transition at high fields. This high field ordered phase in the normal state may originate from a combination of crystalline electric field enhanced Zeeman splitting and quadrupolar ordering. We present an investigation of the electrical resistivity and magnetization of PrOs4Sb12 as a function of temperature between {350 mK} and {3.5 K} and magnetic field up to {18 T}. The data reveal a detailed phase boundary of the high field ordered phase as well as the lower critical field $H_{c1}$ and the onset field of the peak effect in the superconducting state of PrOs4Sb12.