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The structure and magnetic properties of nanocrystalline PrCo3 prepared by high-energy milling technique have been investigated by means of x-ray diffraction using the Rietveld method coupled to Curie temperature and magnetic measurements. The as-milled samples were subsequently annealed in temperature range from 750 to 1050 °C for 30 min to optimize the extrinsic properties. From x-ray studies of magnetic aligned samples, the magnetic anisotropy of this compounds is found uniaxial. The Curie temperature is 349 K and no saturation reached at room temperature for applied field of 90 kOe. The coercive field of 55 kOe and 12 kOe measured at 10 K and 293 K, respectively is obtained after annealing at 750 °C for 30 min suggests that nanocrystalline PrCo3 are interesting candidates in the field of permanent magnets. We have completed this experimental study by simulations in the micromagnetic framework in order to get a qualitative picture of the microstructure effect on the macroscopic magnetization curve. From this simple model calculation, we can suggest that the after annealing the system behaves as magnetically hard crystallites embedded in a weakly magnetized amorphous matrix. [ABSTRACT FROM AUTHOR]

The structure and magnetic properties of nanocrystalline PrCo3 prepared by high-energy milling technique have been investigated by means of x-ray diffraction using the Rietveld method coupled to Curie temperature and magnetic measurements. The as-milled samples were subsequently annealed in temperature range from 750 to 1050 °C for 30 min to optimize the extrinsic properties. From x-ray studies of magnetic aligned samples, the magnetic anisotropy of this compounds is found uniaxial. The Curie temperature is 349 K and no saturation reached at room temperature for applied field of 90 kOe. The coercive field of 55 kOe and 12 kOe measured at 10 K and 293 K, respectively is obtained after annealing at 750 °C for 30 min suggests that nanocrystalline PrCo3 are interesting candidates in the field of permanent magnets. We have completed this experimental study by simulations in the micromagnetic framework in order to get a qualitative picture of the microstructure effect on the macroscopic magnetization curve. From this simple model calculation, we can suggest that the after annealing the system behaves as magnetically hard crystallites embedded in a weakly magnetized amorphous matrix. [ABSTRACT FROM AUTHOR]

Abstract: The structure and magnetic properties of ball-milled and subsequently annealed Sm2Fe17–x M x compounds (M = Si, Ga, Co, Cr, Zr, Mo, for x = 2) were investigated by X-ray diffraction coupled with magnetic measurements and Mössbauer spectroscopy. Rietveld analysis have shown that all these samples crystallize in the Th2Zn17 type rhombohedral structure. The substituting elements Si, Ga, Co occupy the 18h atom site, while Cr, Zr, Mo prefer the 6c site. Mössbauer studies corroborate these results. The X-ray analysis cannot solve the possible M atom distribution over Fe atom sites when atomic factors of Fe and M are close. Mössbauer spectroscopy appears as the efficient tool to raise this ambiguity. The Curie temperature increases upon Zr and Cr substitution reaching a maximum for x = 1, then decreases because of magnetic dilution. [Copyright &y& Elsevier]