Effect of hydrogen as interstitial element on the magnetic properties of some iron rich intermetallic compounds

▶ The iron rich rare-earth-iron intermetallic compounds have been found to present potential for many applications among which one can cite: permament magnet applications, magnetostriction or more recently giant magnetocaloric effect. All these properties are based on the combination of the localized and itinerant magnetism of the R and Fe atoms respectively. Hydrogen insertion can be performed in many of theses phases and could be use to optimise the physical properties. We present here a study of the effect of hydrogen on the RFe11Ti compounds and a comparison with other iron rich intermetallics. ▶ In the alloy, two kinds of linear dependence of the Curie temperature are observed versus the de Gennes factor, one for the light and one for the heavy rare-earth containing compounds. Similar behaviour is observed for the corresponding hydrides but a significant reinforcement of the Fe contribution to the ordering temperature is observed. ▶ Hydrogen insertion leads to an anisotropic unit cell increase which reveals the compacity of the RFe11Ti structure. ▶ We show that in the RFe11Ti like in many other (but not all) iron rare-earth iron rich intermetallic hydrogen insertion leads to a slight increase of the Fe magnetization and an evolution towards more localized magnetic character. ▶ The properties of thee RFe11TiH hydrides are compared to that of other series of iron rich intermetallic hydrides.