Magnetic structure of selected Gd intermetallic alloys from first principles

Abstract

Using first-principles calculations, based on disordered local moment (DLM) theory combined with the self-interaction corrected local spin density approximation (SIC-LSDA), we study magnetic correlations in the paramagnetic state of GdX (X =Cu, Zn, Ga, Ag, Cd, In, Au, Hg, and Tl) intermetallics and their alloys. The predicted magnetic orders and ordering temperatures that these correlations lead to are in overall good agreement with available experiments. The interactions between the Gd f-electron local moments are mediated by the valence electrons of the intermetallics which comprise both Gd and X d bands as well as sp bands. There are RKKY-like features such as dependence on the number of sp-valence electrons but other variations manifest themselves in the phase diagrams as regions of incommensurate magnetic ordering, the origin and range of which are related to the binding energies of the alloying anion d states, and their propensity to hybridize with the Gd states at the Fermi level.

Crucial role of d−d Coulomb correlations in the magnetocaloric ferrimagnets Gd6(Mn1−xNguyen, Yang, Wang et al. 2024Phys. Rev. B2000View full textAdd to dashboardCite

“…2-4. However, the changes seen in the HAXPES spectra are attributed to the TM 3d states as the Gd 5d states usually have a large bandwidth of 5 eV and a relatively small electron count ( 0.3 electrons) in Gd intermetallics [63][64][65], as is also obtained in our electronic structure calculations discussed later. As seen in Fig.…”

First-order magnetic phase transition in Pr2In with negligible thermomagnetic hysteresis

“…The indirect 4 f −4 f interactions in Pr 2 In responsible for the long-range magnetic ordering are conventional. They are mediated by Pr 4 f −Pr 5d polarization and 5d−5d exchange interaction between neighboring Pr atoms [24,25]; hence the role of In in developing FM order is limited to the stabilization of the hexagonal lattice with interatomic distances supporting positive magnetic-exchange energy. This view is also reflected in our DFT results that show a negligible contribution of In in the total DOS near E F (Fig.…”

“…In lanthanide-based materials, the 4 f electronic states are highly localized, and indirect magnetic exchange occurs through Ruderman-Kittel-Kasuya-Yosida (RKKY)-type interactions [22,23] where 5d electrons of the lanthanides play a vital role in the indirect exchange [24,25]. The longrange magnetic order of trivalent lanthanide ions is therefore strongly dependent on the 4 f −5d hybridization and is generally supported by itinerant s, p, and d electrons.…”

“…For example, the crystallographic symmetry of orthorhombic Eu 2 In remains unperturbed across the transition. In rare-earth-based compounds with no transition elements, the magnetic order is nearly exclusively supported by indirect 4 f −4 f coupling of lanthanide ions mediated by 4 f −5d exchange and 5d−5d interactions between neighboring rare-earth ions [24,25,29]. However, the scenario observed in Eu 2 In is more complicated.…”

Large anomalous Hall effect induced by gapped nodal lines in GdZn and GdCd

“…In previous studies, several kinds of ferromagnetic and ferrimagnetic materials with the Weyl points near the Fermi level were reported to show large intrinsic AHE 18,19,[46][47][48][49][50][51][52] 25 and GdCd (265 K) 26 are both higher than that of Fe 3 GeTe 2 (220 K) 20 , which facilitates their experimental observation. Second, the intrinsic AHC of GdZn (GdCd) resulting from the gapped nodal lines can reach − 1260 (−1300) Ω −1 cm −1 at 0.315 (0.270) eV above the Fermi level, where the Fermi level can be easily tuned into the nodal line gaps by alloying 55 . Third, since GdZn and GdCd are isotropic ferromagnets, the anisotropy of the AHC can be easily controlled by the magnetization direction (Fig.…”