ABSTRACT
We report the attainment of the ferromagnetic state in an interstitially modified heavy rare-earth-iron intermetallic compound in an external magnetic field. The starting composition is RE2Fe17, which is the RE-Fe binary richest in iron. We concentrate on the Tm-Fe compound, which is the most sensitive to magnetic field. The maximum possible amount of hydrogen (5 at.H/f.u.) is inserted into a Tm2Fe17 single crystal. We demonstrate that in a magnetic field of 57 T Tm2Fe17H5 reaches the ferromagnetic state with an enviably high polarization of 2.25 T.
ABSTRACT
Gadolinium is a nearly ideal soft-magnetic material. However, one cannot take advantage of its properties at temperatures higher than the room temperature where Gd loses the ferromagnetic ordering. By using high-purity bulk samples with grains ~200 nm in size, we present proof-of-concept measurements of an increased Curie point (TC) and spontaneous magnetization in Gd due to hydrogenation. From first-principles we explain increase of TC in pure Gd due to the addition of hydrogen. We show that the interplay of the characteristic features in the electronic structure of the conduction band at the Fermi level in the high-temperature paramagnetic phase of Gd and "negative" pressure exerted by hydrogen are responsible for the observed effect.
ABSTRACT
An experimental study of correlations between the magnetovolume effects and the type of magnetic ordering in the Lu(2)Fe(17)-based intermetallics is shown for the example of variation of the interatomic distances by means of substitution of Ce for Lu, hydrogenation and subsequent high-pressure investigation of both the initial (Lu(0.8)Ce(0.2))(2)Fe(17) and a hydride (Lu(0.8)Ce(0.2))(2)Fe(17)H(0.4) single-crystalline compounds. The magnetization study was carried out under hydrostatic pressures of up to â¼ 0.8 GPa. Hydrogenation is found to totally suppress the antiferromagnetic order of (Lu(0.8)Ce(0.2))(2)Fe(17) by favoring domination of the ferromagnetic interactions which increases the magnetic ordering temperature from 247 to 300 K. The application of pressure decreases the Curie temperature and induces the non-collinearity of the magnetic moments in (Lu(0.8)Ce(0.2))(2)Fe(17)H(0.4), confirming the strong influence of hydrogenation on exchange coupling.
