Magnetic order and multipole interactions in CexPr1-xB6 solid solutions

TL;DR

This study investigates magnetic structures and multipole interactions in CexPr1-xB6 solid solutions using neutron diffraction, revealing how magnetic order varies with composition and temperature, highlighting the interplay of dipole and multipole interactions.

Contribution

It provides detailed insights into the evolution of magnetic structures across different compositions and temperatures in CexPr1-xB6, emphasizing the role of multipole interactions.

Findings

Incommensurate magnetic structures dominate for x ≤ 0.7.

A crossover to CeB6-like behavior occurs near x=0.7-0.8.

Incommensurate magnetic order persists into the antiferroquadrupolar phase.

Abstract

Magnetic ordering phenomena in CexPr1-xB6 solid solutions have been studied using both powder and single-crystal neutron diffraction. A variety of magnetic structures are observed depending on temperature and Ce concentration. Over a broad composition range (x $\le$ 0.7), Pr-Pr interactions play a dominant role, giving rise to incommensurate structures with wave vectors of the form k{IC1}=(1/4-delta, 1/4, 1/2) or k{IC2}=(1/4-delta, 1/4-delta, 1/2). The crossover to a CeB6-like regime takes place near x = 0.7-0.8. For the latter composition, the antiferroquadrupolar phase transition observed in transport measurements precedes the onset, at lower temperature, of a commensurate magnetic order similar to that existing in CeB6. However, unlike in the pure compound, an incommensurate magnetic order is formed at even higher temperature and persists in the antiferroquadrupolar phase down to the lock-in transition. These results are shown to reflect the interplay between various type of dipole exchange and higher multipole interactions in this series of compounds.