Thermoreversible permanent magnets in the quasibinary GdCo5−xCux system

Abstract

International audienceFerrimagnetic GdCo5-xCux alloys exhibiting the effect of Gd- and 3d-sublattice magnetization compensations at defined temperatures were studied with respect to their use as thermoreversible permanent magnets PMs. Coercive fields 0Hc in the range of 0.3–1.6 T were measured for annealed single crystals with x=1–2.2 having compensation points in the vicinity of room temperature. Two applications of such a thermoreversible PM, namely, a thermally controlled actuator and a contactless temperature sensor, are demonstrated

Cu induced coercivity enhancement in the low viscosity GdCo5−xCux system

“…The maximum of the coercivity occurs for sample D (x ¼1.5) with H c $ 4:2 kOe. A similar behavior was found in annealed single crystals samples, by Grechishkin et al, with H c $ 16 kOe for x¼ 1.5 taken perpendicular to the hard axis of magnetization (parallel to the crystallographic c-axis) [22]. These differences in the coercivity values can be attributed to the polycrystalline character of the samples.…”

Structural and magnetic properties of GdCo5−xNix

“…The coercive field has a broad peak that corresponds with the minimum in magnetization. This behavior is consistent with that observed for single crystals of Cu-doped GdCo 5 , [12,13] and other RECo 5−x Ni x materials [14,15]. A corresponding peak in magnetocrystalline anisotropy is found in the theoretical calculations discussed in Sec.…”

“…Doping a RETM 5 material can change its magnetic properties in a controlled manner [10][11][12][13][14][15][16][17][18][19]. Here, only doping of the TM sublattice is considered.…”

“…Here, only doping of the TM sublattice is considered. The effects of doping on coercive * j.b.staunton@warwick.ac.uk field and saturation magnetization have been studied for single crystals of GdCo 5−x Cu x by Grechishkin et al [12] and later by de Oliveira et al [13]. The Cu reduces the TM sublattice magnetization.…”

First-principles calculations of the magnetocrystalline anisotropy of the prototype 2:17 cell boundary phaseYCo1-x-yFePatrick1, Matsumoto2, Staunton3 2019Journal of Magnetism and Magnetic Materials122181View full textAdd to dashboardCite

“…Finally, we note that although our calculations should ideally be compared to anisotropy constants measured for single crystals, there are a number of experiments which report coercivity enhancement in RE/TM magnets upon addition of Fe or Cu [74][75][76].…”