Resonant x-ray scattering investigation of magnetic ordering inNpAs1 − xSex (x = 0.05, 0.10)

Abstract

A resonant x-ray scattering investigation of theNpAs1 − xSex system with single crystals of 5 and 10% Se content is reported. The main features of themagnetic phase diagram previously studied by neutron scattering were confirmed. Thecoexistence within a single domain of ferro- and antiferro-components in the low-T ferrimagnetic phase was established, as well as the single-k character of the incommensurate phase and of the antiferromagnetic component of theferrimagnetic phase. A tetragonal lattice distortion was found in the ferro- and ferrimagneticphases which is not compatible with the proposed model for the ferromagnetic phase.The study of ferromagnetism was carried out using polarization analysis of thediffracted beam to separate the scattering intensities originating from magnetism andcharge, which are superimposed in reciprocal space. The magnetic character of theferromagnetic signal calculated from the measured intensities in the polarization analysisσπ andσσ channels was confirmed by analysis of the corresponding temperature dependence.