Phase formation and magnetocaloric effect in (Pr,Nd)-Fe alloys prepared by rapidly quenched method

Abstract

In this work, Pr2-xNdxFe17 (x = 0 - 2) ribbons with thickness of about 15 μm were prepared by melt-spinning method. The alloy ribbons were then annealed at different temperatures (900 - 1100°C) for various time (0.25 - 2 h). The formation of the (Pr,Nd)2Fe17 (2:17) crystalline phase in the alloys strongly depends on the Pr/Nd ratio and annealing conditions. Annealing time for the completed formation of the 2:17 phase in the rapidly quenched ribbons is greatly reduced in comparison with that of bulk alloys. Curie temperature, TC, of the alloys can be controlled in room temperature region by changing Pr/Nd ratio. Maximum magnetic entropy change (|ΔSm|max) and full width at haft the maximum peak (FWHM) of the magnetic entropy change of the alloys were respectively found to be larger than 1.5 J.kg−1K−1 and 40 K in room temperature region with magetic field change ΔH = 12 kOe.

Magnetocaloric effect in amorphous-crystalline microcircuits PrDyFeCoB

“…In the field of rare-earth alloys Re−T M−B (Rerare-earth metals, T Mtransition metals, Bboron) a considerable amount of research on the magnetocaloric effect has been done on bulk samples [13][14][15][16][17][18][19][20][21][22][23][24][25]. Studies of micro-magnets exhibiting MCE are not so widely presented in the literature.…”

“…Note that the RCP value in Pr 1.3 Nd 0.7 Fe 17 is comparable in value to the data of our experiments, which is explained by the significant width of the entropy peak in the alloys we study. Magnetocaloric parameters of rare-earth alloys (Curie temperature T c , maximum change in the magnetic component of entropy − S max , RCP) are collected in the Table according to data [13][14][15][16][17][18][19][20][21][22][23][24][25]. It follows from the data presented that the phase transition temperatures investigated in our and other works are close to room temperature.…”

“…Third, in the crystalline state, the tetragonal phase (PrDy) 2 (FeCo) 14 B has a very high coercivity 2−2.5 T at room temperature [13][14][15], which also results from the high single-ion anisotropy of Dy 3+ and Pr 3+ . Since the fundamental cause of the single-ion magnetic anisotropy is the high value of the spin-orbit interaction in Dy 3+ and Pr 3+ ions, one would expect the orbital moment to make an contribution to the magnetic part of the anisotropy and its change in magnetic field in crystallites, which are usually in the amorphous phase, when studying MCE.…”

“…Magnetocaloric parameters of rare-earth alloys (Curie temperature Tc , maximum change in the magnetic component of entropy − Smax, RCP) by data[13][14][15][16][17][18][19][20][21][22][23][24][25] …”