On the Structural and Magnetic Properties of R2Fe17?x(A,T)x (R = Rare Earth; A = Al, Si, Ga; T = Transition Metal) Compounds (original) (raw)
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Structural, magnetic and exchange interaction studies on R2Fe17−xGax (R=Tm, Er and Sm) compounds
Physica B: Condensed Matter, 2000
A detailed investigation of the structure and magnetic properties of R Fe \V Ga V (R"Tm, Er and Sm and x"0}7) was carried out by means of powder X-ray di!raction, magnetization and AC magnetic susceptibility measurements. With increasing Ga content, a structural transformation from hexagonal Th Ni-type structure to rhombohedral Th Zn-type structure is observed in compounds Er Fe \V Ga V (x"0}7) and Tm Fe \V Ga V (x"0}7). The compounds Sm Fe \V Ga V (x"0}7) crystallize in rhombohedral Th Zn-type structure. The Curie temperature increases in the initial Ga concentration range, reaches a maximum and then decreases at higher Ga concentration. The exchange interaction parameter J $ $ reaches a maximum and then decreases whereas the value of J 0$ is almost independent of Ga concentration. X-ray di!raction measurements on magnetically aligned powder samples show a uniaxial anisotropy for compounds with at x"2, 3 and 4 in the Sm Fe \V Ga V series whereas, it was observed for x"7 in the Tm Fe \V Ga V compounds.
Crystallographic and Magnetic Properties of R 2 Fe 17 C x with R=Y, Pr, Nd, Sm, Gd, Dy, and Er
Chinese Physics Letters, 1991
Structural. thermal anti magnetic studies arc reported for the REInAu., scric', (except tEu). (~mlpountl~, with I.m ('c. Ih and Nd show a phase transition from cubic to telragonal structure. All coml~)unds | I[IVC a normal ' alcncc state mzlgllcti... behaviour, except YblnAu: which is confirmed to bc IV with a ground ';tare wilh 2./ t I x, and ("clnAu., which ale';pine t'~ing magnetic has a strongly enhanced eleclron~-,pccilic heal. "l'ernar) RF.MAu_, intcrmelallic,; (Rt! So. la, Y: M = AI, (ia, In) with ('sCI structure were first described by Matthias el al. I I J-Among these,
Journal of Magnetism and Magnetic Materials, 2005
In ternary R 3 Fe 33Àx Ti 3 ðx ¼ 0; 1; . . . ; 7; R ¼ Gd; YÞ and R 3 Fe 33Àx Ti 3 ðR ¼ Tb; Ho; Dy; Er; x ¼ 0; 3; 6; 9Þ alloys, the anomalous wide homogeneous region of ThMn 12 structure has been obtained. The single-crystal samples for each composition R 3 Fe 33Àx Ti 3 were prepared. By means of thermomagnetic analysis, it is shown that the T C of these single crystals monotonically decreases with the decrease in Fe concentration. With the decrease of iron concentration, the magnitude of magnetization saturation steadily decreases too. On the other hand, the temperatures of spin reorientation phases transition T SR for R ¼ Tb; Ho; Dy; Er increase. From this, it follows that by the small changes in the Fe concentration it is possible to make a significant change of parameters of exchange interaction between R and 3d sublattices. r
Intermetallics, 2011
We have synthesized three pseudo-binary (Ce,R)2Fe17 intermetallic alloys, where cerium has been partially substituted by R = Y, Pr and Dy, with the aim of tuning the Curie temperature (between 253 and 273 K) for obtaining the maximum magneto-caloric response of the alloys just below room temperature. The analysis of the x-ray powder diffraction patterns show that the three samples crystallize in the rhombohedral Th2Zn17-type crystal structure (space group View the MathML source). We report the temperature dependence of the isothermal magnetic entropy change, |ΔSM|(T), the magnetic field dependence of its maximum value, |ΔSMmax|(H), and the relative cooling power around the second-order magnetic transition for magnetic field changes μ0ΔHmax = 5 T. The collapse of the normalized ΔSM(θ)/ΔSMmax vs. temperature (where θ is a rescaled temperature) into a single master curve allows the extrapolation of |ΔSM|(T) curves for higher magnetic field changes, and/or the estimation of the temperature dependence of the magnetic entropy for other 2:17 pseudo-binary compounds. The lower values of |ΔSMmax| compared with those of the R2Fe17 compounds with R = Pr or Nd are explained in terms of the decrease of the saturation magnetization. The magnetic field dependence of the |ΔSMmax| indicates that only Pr1.5Ce0.5Fe17 alloy roughly follows a mean-field behaviour.