Rare-earth/transition-metal magnetic interactions in pristine and (Ni,Fe)-doped YCo5 and GdCo5

Abstract

We present an investigation into the intrinsic magnetic properties of the compounds YCo 5 and GdCo 5 , members of the RETM 5 class of permanent magnets (RE = rare earth, TM = transition metal). Focusing on Y and Gd provides direct insight into both the TM magnetization and RE-TM interactions without the complication of strong crystal field effects. We synthesize single crystals arXiv:1708.00288v1 [cond-mat.mtrl-sci]

Temperature-dependent magnetocrystalline anisotropy of rare earth/transition metal permanent magnets from first principles: The light RCo5 (R=Y, La-Gd) intermetallics

“…Comparing in more detail, we find agreement between experimental and calculated κ values to within a few MJm −3 for all but the lowest temperatures, where the classical statistical mechanics of DFT-DLM calculations leads to inaccuracies [37], and high temperatures, where experimentally the compounds might undergo decomposition [27]. We calculate κ 1 at room temperature for SmCo 5 to be 21.…”

First-principles calculations of the magnetocrystalline anisotropy of the prototype 2:17 cell boundary phaseYCo1-x-yFePatrick1, Matsumoto2, Staunton3 2019Journal of Magnetism and Magnetic MaterialsSelf Cite122181View full textAdd to dashboardCite

“…[63] that Fe preferred to occupy 2c sites. Our own CPA calculations performed at zero temperature (ferromagnetic state) find 2c substitution to be preferred for Fe, Cu, and Ni [35] but calculations on stoichiometric systems including optimization of the lattice parameters found Fe to prefer 3g doping and Cu to prefer 2c [64]. Furthermore our test calculations and previous work [65] have shown the energetics to be sensitive to the modeling of the magnetic state (ferromagnetic versus nonmagnetic).…”

“…Finite temperature properties were calculated within the disordered local moment picture, which treats the temperature-induced fluctuations of the local moments at the level of the CPA [44]. The temperature-dependent Weiss fields were determined using an iterative procedure [34,35]. Both an overview of DFT-DLM and the detailed procedure of evaluating the Weiss fields and torque can be found elsewhere, e.g.…”

“…The modification of TM content by the substitution of Co with Cu and Fe can be expected to change the magnetic anisotropy of SmTM 5 in a number of ways, namely: (a) affecting the single ion anisotropy of Sm by modifying the crystal field [28] (b) affecting the temperature dependence of this single ion anisotropy by modifying the exchange field felt by the RE due to the RE/TM interaction [29] and (c) modifying the contribution of the TM-3d electrons to the anisotropy [30][31][32][33][34]. The introduction of Fe and Cu can also be expected to affect the other key micromagnetic parameters A and polarization J, leading for example to modified Curie temperatures [35]. Furthermore, changing the local environment of the Sm atoms may even modify their valency and orbital hybridization, further affecting the anisotropy [36].…”

Rare-earth/transition-metal magnets at finite temperature: Self-interaction-corrected relativistic density functional theory in the disordered local moment picture

“…Meanwhile the problematic RE-4f electrons are treated within DFT using the local self-interaction correction (LSIC) [17]. Previous modeling of REs within this framework has been limited to Gd [18][19][20][21], but the develop-ments described in Section III now allow investigation of the entire RE series for the same computational cost. We use the new theory to study the RECo 5 family of magnets ( Fig.…”