Charge ordering in the intermediate valence magnet YbPd

TL;DR

This study uncovers the charge ordering structure in YbPd, revealing temperature-dependent incommensurate and commensurate phases with specific valence states, advancing understanding of charge order in intermediate valence magnets.

Contribution

The paper identifies the charge ordering structure and valence states in YbPd using x-ray diffraction, providing new insights into its temperature-dependent phase transitions.

Findings

Incommensurate charge order below 130 K

Transition to commensurate order at 105 K

Yb valences of 3+ and 2.6+ below 105 K

Abstract

An x-ray diffraction study reveals the charge ordering structure in an intermediate valence magnet YbPd with a CsCl-structure. The valence of the Yb ions forms an incommensurate structure, characterized by the wavevector (+-0.07 +-0.07 1/2) below 130 K. At 105 K, the incommensurate structure turns into a commensurate structure, characterized by the wavevector (0 0 1/2). Based on the resonant x-ray diffraction spectra of the superlattice reflections, the valences of the Yb ions below 105 K are found to be 3+ and 2.6+. The origin of the long wavelength modulation is discussed with the aid of an Ising model having the second nearest neighbor interaction.