Magnetic order in the filled skutterudites RPt4Ge12 (R = Nd, Eu)

TL;DR

This study investigates the magnetic properties of NdPt4Ge12 and EuPt4Ge12 skutterudites, revealing multiple magnetic phase transitions and detailed electronic ground states through specific heat and susceptibility measurements.

Contribution

It provides new experimental insights into the magnetic phase diagram and electronic ground states of NdPt4Ge12 and EuPt4Ge12 skutterudites.

Findings

NdPt4Ge12 exhibits two magnetic phase transitions at 0.67 K and 0.58 K.

EuPt4Ge12 shows a complex magnetic phase diagram below 1.78 K.

NdPt4Ge12 has a quartet crystalline electric field ground state.

Abstract

Rare-earth metal filled skutterudites RPt4Ge12 with R=La-Nd, and Eu exhibit a variety of different ground states, e.g., conventional and unconventional superconductivity in LaPt4Ge12 and PrPt4Ge12, respectively, and intermediate valence behavior in CePt4Ge12. In this work we investigate the magnetic state of NdPt4Ge12 and EuPt4Ge12 by specific heat, dc-susceptibility and magnetization. NdPt4Ge12 shows two magnetic phase transitions at T_N1=0.67 K and T_N2=0.58 K, while EuPt4Ge12 displays a complex magnetic phase diagram below the magnetic ordering temperature of 1.78 K. The specific heat indicates that in NdPt4Ge12 the crystalline electric field (CEF) ground state of the Nd3+ is a quartet and that, as expected, in EuPt4Ge12 the Eu2+ state is fully degenerate.