Work

Modification of the magnetic properties of PrScSi and NdScSi silicides induced by oxygen and hydrogen insertion via water vapor dissociation

Year: 2026

Type: article

Abstract: Insertion of oxygen and hydrogen atoms into vacant octahedral and tetrahedral interstitial sites was observed after heating under air the silicides RScSi (R = rare-earth) in the temperature range 315-350 °C. In a previous study with R = La, this insertion was proposed to proceed through the dissociation of water vapor molecules. In this work, we have studied three samples with the compositions PrScSiO 0.35(1) H 0.38(1) , PrScSiO 0.40(1) H 0.81(2) and NdScSiO 0.26(1) H 0.79(1) . These compositions were determined from the nuclear structure refinement of neutron diffraction data. It has been confirmed, as previously observed for the La phase, that oxygen atoms are located into R 4 Sc 2 octahedral sites and hydrogen atoms in R 4 tetrahedral sites. Magnetic and specific heat measurements have evidenced huge variation of the physical properties of the pristine phases NdScSi and PrScSi after the insertion of O and H atoms. For PrScSi, the antiferromagnetic order with T N = 145 K is changed into a ferromagnetic one with a strong decrease of the ordering temperature for PrScSiO 0.35 H 0.38 (T C = 69 K). Increasing the H and O content in PrScSi leads to the suppression of magnetic order for PrScSiO 0.40 H 0.81 . By contrast, an opposite evolution of the magnetic ordering type is evidenced for NdScSi. While NdScSi exhibits a ferromagnetic ordering below T C = 175 K, NdScSiO 0.26 H 0.79 undergoes an antiferromagnetic ordering at T N = 3 K.

Source: Journal of Alloys and Compounds

DOI: 10.1016/j.jallcom.2026.191215

Authors: Sophie Tencé, Khaled Alabd, Baptiste Vignolle, Vivian Nassif, Emmanuelle Suard, Etienne Gaudin