First-principles calculations of the magnetic properties of and its hydrides

Abstract

Self-consistent, general potential, electronic structure calculations have been performed for the Laves phase compound YMn 2 and its hydrides YMn 2 H x (x = 0.5 and 1.0). The parent material, YMn 2 , is found to be an itinerant antiferromagnet with a magnetic moment of 2.6µ B per Mn atom whereas for the hydrides an additional ferrimagnetic component appears. This is in good agreement with experiment. The dependence of the calculated atom-projected magnetic moments and hyperfine fields on the Mn-H interaction is analysed. We have also calculated the total energy for three different H positions and established that the lowest energy is found for the experimentally observed position.

Structural and Magnetic Properties of Low D Content YMn2 Deuteride

“…This is obviously connected to the H concentration, and for a better understanding of the magnetic properties, the e!ect of "lling the 3d band with electrons coming from the hydrogen should be considered. Band structure calculations (19) have shown that for YMn hydrides, an additional ferrimagnetic component must appear. Unfortunately, such calculations do not make it possible to explain the collinear or noncollinear behavior of the magnetic structure.…”

Electronic density of states of YMn2Hx compounds

“…Main features are the same, but their shapes differ that is a result of different number of H atoms in close distance from the particular Mn atom. Pajda et al [1] suggested that H atoms acted as donors in the YMn 2 H x compounds for x = 0.5 and 1 because in their calculations the Fermi energy was slightly rising upon hydrogenation. In our case, i.e.…”

“…fications for the Laves phase of RMn 2 compounds. Such DOS calculations were previously done by Pajda et al [1] for YMn 2 H x (x = 0.5 and 1). Here we present our calculations for this hydride with higher hydrogen content (x = 1.5, 2, 2.5 and 3).…”

Recovery of the magnetic ordering inY1−xCexMn<

“…13,14 Then, a conciliatory scheme to account for the anomalous behavior of the YMn 2 upon chemical substitution of Mn or interstitial hydrogen doping can be obtained in terms of the interplay of both the increase in the Mn-Mn distance and the electronic modification induced by chemical substitution into the DOS modification. 15,16 Trying to obtain a deeper insight into the mechanisms responsible for the unusual response of YMn 2 to external parameters we have tailored a series of Y 1Ϫx Ce x Mn 2 hydrides. As the electronic state of cerium is very sensitive to hydrogen absorption, the DOS of the system would become even more dependent on the Mn-H hybridization due to the existence of the Mn(3d)-Ce(5d) hybridization.…”

“…In particular, Pajda et al have recently revealed the existence of a competition between the Mn-H hybridization, favoring reduced Mn magnetic moments, and the increased lattice constants producing larger Mn moments. 16 Within this framework, the presence of cerium is of particular significance because of the peculiar magnetic behavior of the CeM 2 systems (M ϭ3d transition metal͒. This depends on the strength of the hybridization between the d states of the transition metal and the cerium 4 f and 5d states.…”