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Single-phase Gd[sub 2]Co[sub 17-x]V[sub x] compounds (x = 0.0-1.5) crystallizing in the rhombohedral Th[sub 2]Zn[sub 17] structure have been synthesized. The lattice parameters a and c of the compounds increase linearly with increasing V content, and the rate of increase of c is about 2.5 times as large as that of a. Substitution of a small amount of V atoms (x = 0.3) for Co atoms leads to the occurrence of uniaxial magnetocrystalline anisotropy of Gd[sub 2]Co[sub 17-x]V[sub x]. The anisotropy field H[sub A] increases drastically with increasing V content. The variations of both the lattice parameters and the magnetocrystalline anisotropy with V content suggest a preferential occupation of the V atoms at the 6c dumbbell site. The Curie temperature T[sub C], saturation moment M[sub S], and average Co moment 〈μ[sub Co]〉 of the compounds decrease greatly as the V content increases. The rapid decrease of T[sub C] is essentially attributed to a serious weakening of the Co-Co interactions due to the preferential occupation of the V atoms at the 6c site. The effect of a strong hybridization between the V and Co atoms is plausibly responsible for the decreases of the Ms and 〈μ[sub Co]〉. [ABSTRACT FROM AUTHOR]

The crystal structure and superconducting properties of RuSr[sub 2-x]Ba[sub x]GdCu[sub 2]O[sub 8] (0<=x<=0.1) have been investigated. X-ray powder diffraction (XRD) patterns show that the solid solution range is 0<=x<=0.1. The superconducting transition temperature was raised up to 35 K (zero) and 62 K (onset) for x=0.07, from 16 K (zero) and 45 K (onset) for x=0.0, and then T[sub C] decreases with x when x>0.07. Rietveld refinement for XRD data of RuSr[sub 2-x]Ba[sub x]GdCu[sub 2]O[sub 8] show that the apical Cu–O(1) bond length increases with an increase of x, while the Ru–O(1) bond length decreases, This may account for the enhancement of the superconducting transition temperature. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Crystal structure and magnetic properties of the NdCo[sub 9.5-x]Fe[sub x]V[sub 2.5] compounds with x=0–3.5 have been investigated. The lattice parameters increase linearly with the Fe content and the Curie temperature increases substantially at small amount of Fe content and then gradually with the further increase of x. A domain-wall pinning phenomenon was observed in all of the compounds and becomes less obvious as x increases. At a higher field, the compounds exhibit a field-induced metamagnetic transition. The critical field for the metamagnetic transition increases first then decreases with the Fe content, whereas the difference of the magnetization between 14 and 5 T increases with x. The observation can be understood by considering an interplay of the volume expansion, enhanced exchange coupling parameter J[sub RT] and the T sublattice moment μ[sub T] due to the Fe substitution for Co. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]