Magnetocaloric properties of (La,RE)Fe11.4Si1.6 compounds (RE=Y,Gd)

Abstract

The mechanosynthesis process has been applied in theLaFe11.4Si1.6 compound to reduce the undesirable segregated rich-Fe phases that impair its application as a solid magnetic refrigerant. The influence of La substitution (5 at. %) by Y or Gd atoms on the magnetic and magnetocaloric properties has been also studied. Y- and Gd-substituted compounds have a magnetic ordering temperature higher than the pure La compound. While the Y-substituted compound keeps a first-order-like magnetic transition feature, the Gd-substituted one seems to suppress it. The maximum value of the magnetic entropy change of the Y compound is roughly the same as the La compound (−18 J∕kg K) but with a magnetic entropy change peak significantly broader. For the Gd-compound case a drastic reduction of the magnetic entropy change (−7 J∕kg K) is found.

Structural and magnetic properties of magnetocaloric LaFe13–xSix compounds synthesized by high energy ball-milling

“…Fig. 11 shows the magnetic entropy variation of LaFe 13ex Si x compounds as a function of temperature in magnetic field change of 0e2 T and 0e5 T. The maximum peak values of DS M for the LaFe 13ex Si x compounds with x ¼ 1.4 and 1.6 are respectively 32.6 and 25.0 J/kg K under a magnetic field change of 0e5 T. These values are higher than that reported for the corresponding bulk compound under the same magnetic field change (respectively 24 [30] and 18 J/kg K [31]). …”

Analysis of the Magnetocaloric Effect in Powder Samples Obtained by Ball Milling

“…Among RE-based materials Gd 5 Si 2 Ge 2 , [13,14] La(FeSi) 13 , [15][16][17][18] RE 2 Fe 17 intermetallics, [19,20] clathrates Eu 8 Ga 16 Ge 30 , [21] and amorphous alloys [13,14,22] can be found. Among TM-based systems Heusler alloys, [23][24][25] MnAs, [26][27][28][29] cFeNi, [30][31][32] and amorphous alloys [33][34][35][36][37] can be found.…”

“…[13] The use of BM can be found in the literature as a single-step production technique (e.g., amorphous alloys). However, annealing can be necessary to produce the desired phase and then BM is used as a first step to prepare a well-mixed system (e.g., BM reduces the annealing time in La(Fe,Si) 13 alloys [15,16] ) or as a final step in a reactive milling process (e.g., forming hydrides in La(Fe,Si) 13 H d [17,18] ). Some examples of the different MCE results achieved on ball-milled samples are summarized in Table I.…”

Magnetocaloric Properties Response in High-Speed Melt-Spun La-Ce-Fe-Si Ribbons

“…[9][10][11][12][13] Partial substitutions of La by Ce, Pr, Nd or Gd have resulted in large increases in the MCE. [14][15][16][17][18] It is generally accepted that the large MCE of La(Fe x Si 1Àx ) 13 originates mainly from the NaZn 13 -type structure (known as the 1:13 phase). In reality, however, it is difficult to form the 1:13 phase directly from a common solidification process due to the incomplete peritectic reaction.…”