Abstract
Intermetallic compounds of Dy2Fe16Ga1−xNbx (x = 0.0 to 1.00) were synthesized by arc melting. Samples were investigated for structural, magnetic, and hyperfine properties using X-ray diffraction, vibration sample magnetometer, and Mossbauer spectrometer, respectively. The Rietveld analysis of room temperature X-ray diffraction data shows that all the samples were crystallized in Th2Fe17 structure. The unit cell volume of alloys increased linearly with an increase in Nb content. The maximum Curie temperature Tc ~523 K for x = 0.6 sample is higher than Tc = 153 K of Dy2Fe17. The saturation magnetization decreased linearly with increasing Nb content from 61.57 emu/g for x = 0.0 to 42.46 emu/g for x = 1.0. The Mössbauer spectra and Rietveld analysis showed a small amount of DyFe3 and NbFe2 secondary phases at x = 1.0. The hyperfine field of Dy2Fe16Ga1−xNbx decreased while the isomer shift values increased with the Nb content. The observed increase in isomer shift may have resulted from the decrease in s electron density due to the unit cell volume expansion. The substantial increase in Tc of thus prepared intermetallic compounds is expected to have implications in magnets used for high-temperature applications.
Highlights
We proposed studying the co-substitution of Ga and Nb in the Dy2 Fe17 compound to increase Tc values further
The X-ray powder diffraction (XRD) results and the Rietveld refinements show that the samples have a Th2 Ni17 -type structure
The XRD patterns show the presence of impurities phases DyFe3 and NbFe2 at higher Nb content (x > 0.80) only, which is confirmed by Mossbauer spectral analysis
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. (2:17) alloy has the most Fe-content among all R-iron intermetallic and they have the highest Ms in the class of intermetallic magnets These compounds have relatively low Curie temperature, Tc. For example, Tc ~473 K for Gd2 Fe17 and 370 K for. Various strategies have been employed to address issues related to improving magnetic anisotropy, magnetization, and Curie temperature of R2 Fe17 compounds. Efforts in this direction include insertion of metalloids, hydrogen, nitrogen, and carbon in the R2 Fe17 matrix [2,3,4,5]. The study is critical in developing futuristic applications demanding high-temperature operation of magnets such as fast-breeder reactors, ion propulsion engines for spacecraft
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