Investigation on structural and magnetocaloric properties of LaFe13-xSix(H,C)(y) compounds

The first part of this study is devoted to LaFe13-xSixHy hydrides. The parent intermetallic alloys were synthesized by high energy ball milling. The insertion of H atoms was carried out by solid/gas reaction using a Sievert apparatus. Their thermodynamic properties show a very fast kinetic absorption at 298 K under 10 bars depending on Si content. The structural results combined with magnetic measurements allow to explain the magnetovolumic effect on the Curie temperature. The second part of this study is dedicated to LaFe13-xSixCy carbides. They were synthesized by solid/solid reaction between the inter metallic powder and the anthracene. Their structural as well as magnetocaloric properties were investigated. Further structural and magnetic results were carried out by neutron diffraction. A complete crystallographic characterization was made. The cell parameter and the Fe magnetic moments versus temperature were determined. Moreover, the misunderstanding on interstitial site was clear up.) (C) 2015 Published by Elsevier Inc.