Structural and magnetic properties ofGdCo5−xNix

Abstract

GdCo 5 may be considered as two sublattices-one of Gd and one of Co-whose magnetizations are in antiparallel alignment, forming a ferrimagnet. Substitution of nickel in the cobalt sublattice of GdCo 5 has been investigated to gain insight into how the magnetic properties of this prototype rare-earth/transition-metal magnet are affected by changes in the transition-metal sublattice. Polycrystalline samples of GdCo 5−x Ni x for 0 x 5 were synthesized by arc melting. Structural characterization was carried out by powder x-ray diffraction and optical and scanning electron microscope imagings of metallographic slides, the latter revealing a low concentration of Gd 2 (Co, Ni) 7 lamellae for x 2.5. Compensation-i.e., the cancellation of the opposing Gd and transition-metal moments-is observed for 1 < x < 3 at a temperature which increases with Ni content; for larger x, no compensation is observed below 360 K. A peak in the coercivity is seen at x ≈ 1 at 10 K coinciding with a minimum in the saturation magnetization. Density-functional theory calculations within the disordered local moment picture reproduce the dependence of the magnetization on Ni content and temperature. The calculations also show a peak in the magnetocrystalline anisotropy at similar Ni concentrations to the experimentally observed coercivity maximum.

First-principles Calculation of Magnetocrystalline Anisotropy of Y(Co,Fe,Ni,Cu)$_5$ Based on Full-potential KKR Green's Function Method

“…4(b), decreases drastically as the copper content increases. in Gd(Co 1−z Ni z ) 5 [48]. The theoretical calculation indicates that the nickel at the 2c-site enhances the K u in the gadolinium system.…”

Efficient Algorithm Based on Liechtenstein Method for Computing Exchange Coupling Constants Using Localized Basis Set

“…Recently, first principles computation techniques have been employed to investigate the magnetic properties of permanent magnets [10][11][12][13][14][15][16][17][18][19][20][21]. It is, however, still difficult to understand the details of magnetic interaction in the microstructures of permanent magnets because of their structural complexity.…”