Effect of Al and Si substitutions on the magnetic properties of SmTbFe17
TL;DR: The structural and magnetic properties of SmTbFe17−xAlx (x=0-8) and SmtbFe 17−x6 (x = 0-3.5) were investigated by x-ray-diffraction and magnetization studies.
Abstract: The structural and magnetic properties of SmTbFe17−xAlx (x=0–8) and SmTbFe17−xSix (x=0–3.5) were investigated by x-ray-diffraction and magnetization studies. All the compounds stabilize in rhombohedral structure. The lattice parameters are found to increase with Al substitution whereas they are found to decrease with Si substitution. The rates of the decrease of saturation magnetization (Ms) value with the substitution of Al and Si are almost the same. The easy direction of magnetization (EMD) is in the ab plane up to an Al concentration of x=7 and has a tendency to shift towards the c axis at x=8. All the compounds with Si are seen to have the EMD in the ab plane. Electron-magnon scattering is seen to contribute to the electrical resistivity in both Al- and Si-substituted compounds; in the temperature range of 30–60K and at higher temperatures, scattering due to phonons is observed.
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TL;DR: The results of X-ray diffraction studies and magnetic measurements performed on Y 2 Fe 17-x M x compounds with M = Al, Ga or Si as well as on their nitrides are reported in this paper.
32 citations
TL;DR: In this paper, the effect of Al substitution in Nd2Fe17 compound by means of first-principles calculations was studied, and it was shown that the Al moment is oppositely polarized to Fe.
Abstract: We have studied the effect of Al substitution in Nd2Fe17 compound by means of first‐principles calculations. We first obtain the site‐decomposed potentials for Fe from self‐consistent calculation on Y2Fe17 and the atomiclike potentials in the crystalline environment for Al and Nd. Calculations are carried out for a single Al substituting one Fe at four different Fe sites (6c), (9d), (18f ), and (18h), two Al substituting two Fe (18h), and four Al substituting three Fe (18h) and one Fe (18f ). Our results show that the Al moment is oppositely polarized to Fe. The average moment per Fe atom actually increases for Al substituting Fe (18h) and Fe (18f ) is about the same for Al substituting Fe (6c), and is drastically reduced when replacing Fe (9d). Experimentally, Al is shown to be excluded from the (9d) sites because of the small Wigner–Seitz volume. When two Fe atoms are replaced by two Al atoms, the total moment is only slightly less than when only one Fe atom is replaced, and the Ms per Fe site actually ...
24 citations
TL;DR: In this paper, the intersublattice molecular field has been calculated for the rich Fe−4f compounds on the basis of a value of 6.72 K for this parameter as derived from high magnetic field studies.
Abstract: Some experimental evidence is given to show that the3d-4f spin coupling parameter is rather insensitive to the kind of the rare earth spin and iron composition in the RnFem intermetallics. The intersublattice molecular field has been calculated for the rich Fe−4f compounds on the basis of a value of 6.72 K for this parameter as derived from high magnetic field studies. This field affects the R magnetic moment and originates from iron sublattice in the R2Fe17, R6Fe23, RFe3 and RFe2 compounds. The values of the field for the new magnetic materials of the R2Fe14B type have also been calculated.
22 citations
TL;DR: In this article, an x-ray diffraction study of (Pr0.5Er 0.5)2Fe17−xAlx (0≤x≤10) shows an expansion of its unit cell with x. This effect may be due to the charge transfer from Al to the 3d band of Fe.
Abstract: An x‐ray diffraction study of (Pr0.5Er0.5)2Fe17−xAlx (0≤x≤10) shows an expansion of its unit cell with x. The crystal structure changes from hexagonal Th2Ni17 to rhombohedral Th2Zn17 at x=6. The magnetic moment decreases by increasing the Al concentration. This effect may be due to the charge transfer from Al to the 3d band of Fe. The Curie temperatures are found to increase with Al up to x=3 and then decrease up to x=10, and the possible underpinning mechanisms are discussed. X‐ray diffractograms of the magnetically aligned samples indicate that the easy magnetization directions of the samples with x=1,2,3, and 4 lie on a cone about the c axis. Electrical resistivity measurements show that the residual resistivity increases drastically with the Al concentration. The temperature coefficient of resistivity becomes almost zero for intermediate Al concentrations.
21 citations
TL;DR: In this paper, electrical resistivity studies were carried out on (Er 1− x Pr x ) 2 Fe 17 (0.4 ⩽ x⩽ 1.0) compounds and they all possess metallic behavior in the temperature range 16-400 K.
20 citations