Magnetic Characteristics of Some Binary and Ternary 2–17 Compounds

Abstract

The magnetic anisotropy of R2Co17 and R2Co17−xTx compounds with R=Y, Ce, Pr, Nd, Th and T=Mn, Fe has been investigated. The directions of easy magnetization were determined by x-ray studies on oriented powders. The several R2Co17 compounds, except for Ce2Co17, have an easy basal plane; the behavior of Ce2Co17 could not be clarified. Replacement of Co by Mn or Fe changes the easy magnetization direction from the basal plane to the c axis. Anisotropy fields were measured on magnetically aligned powders. The values for the anisotropy fields range between 12 and 24 kOe. Curie temperatures and saturation magnetization data for R2Co17−xTx compounds with T=Mn, Ru and R=Ho, Y are reported. The decrease of the magnetization with increasing x observed in the system Y2Co17−xTx is accounted for by assuming either a reduced Co moment or an antiparallel coupling of the T transition-metal spin. Similar considerations hold for Ho2Co17−xTx ternaries.

Spin reorientation and magnetic anisotropy in Y2Co17−xCrx (x=1.17–3.0) compounds

“…A strong uniaxial magnetic anisotropy is required for achieving high coercivity, while the binary R 2 Co 17 compounds exhibit a weak uniaxial anisotropy only for the compounds with R = Sm, Er and Tm. Recently, it was found that the substitution of Al, Ga and Si for Fe could not only significantly increase the Curie temperature of R 2 Fe 17 , but it was also found that such substitutions can cause a change in the easy magnetic direction (EMD) from the basal plane to the c-axis in R 2 T 17−x M x (R = Y, Er, Pr, Ho, Dy; T = Fe, Co; M = Al, Ga, Si) [11][12][13][14][15][16]. Zhang et al [17] studied the influence of substitution of small amounts of Ti, V, Cr, Cu, and Mo for Co on the magnetic properties of Y 2 Co 17 and found that the magnetic anisotropy can be correlated with the metallic radius of the element substitution for Co.…”

Magnetic properties of Sm2Co17−xCrx (0 ≤ x ≤ 3.0) compounds

“…A strong uniaxial magnetic anisotropy is required for achieving high coercivity, the binary R 2 Co 17 compounds exhibiting uniaxial anisotropy only for R = Sm, Er, and Tm. Recently, it was found that the substitution of Al, Ga, and Si for Fe could not only significantly increase the Curie temperature of R 2 Fe 17 , but also cause a change in the easy magnetic direction (EMD) from the basal plane to the c-axis in R 2 T 17−x M x (R = Y, Er, Pr, Ho, Dy, T = Fe, Co, M = Al, Ga, Si) [11][12][13][14][15][16]. Wang et al [17] found that the Curie temperature and the unit-cell volume decreases monotonically with substitution of Si for Co.…”

Crystal structure and magnetic properties of Lu2Co17−xSix single crystals

“…In the previous studies it was revealed that for R 2 Co 17 compounds, a partial substitution of the other 3d transition metals [4], as well as substitutions of Al, Si and Ga [5][6][7] for Co lead in some cases to a sign reversal of the magnetocrystalline anisotropy (MCA) of the Co sublattice from the easy-plane to the easy-axis. Within a single-ion approximation [8], R 2 Co 17 compounds can be considered as two-sublattice magnets, and thus, a study of R 2 (Co,M) 17 (M is a substitution element) compounds with non-magnetic R (Ce 4þ , Lu 3þ or its analogue Y 3þ ) and Gd 3þ (Gd 3þ has a magnetic moment but being in the s-state doesn't posses the orbital moment, thus doesn't contribute to the anisotropy) provides information on the Co sublattice anisotropy and on the influence of substitution atoms on MCA.…”