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Title: Magnetocaloric effect of Gd4(BixSb1-x)3 alloy series

Thesis/Dissertation ·
DOI:https://doi.org/10.2172/754836· OSTI ID:754836
 [1]
  1. Iowa State Univ., Ames, IA (United States)

Alloys from the Gd4(BixSb1-x)3 series were prepared by melting a stoichiometric amounts of pure metals in an induction furnace. The crystal structure is of the anti-Th3P4 type (space group I$$\bar{4}$$3d) for all the compounds tested. The linear increase of the lattice parameters with Bi concentration is attributed to the larger atomic radius of Bi than that of Sb. Magnetic measurements show that the alloys order ferromagnetically from 266K to 330K, with the ordering temperature increasing with decreasing Bi concentration. The alloys are soft ferromagnets below their Curie temperatures, and follow the Curie-Weiss law above their ordering temperatures. The paramagnetic effective magnetic moments are low compared to the theoretical value for a free Gd3+, while the ordered magnetic moments are close to the theoretical value for Gd. The alloys exhibit a moderate magnetocaloric effect (MCE) whose maxima are located between 270K and 338K and have relatively wide peaks. The peak MCE temperature decreases with decreasing Bi concentration while the peak height increases with decreasing Bi concentration. The Curie temperatures determined from inflection points of heat capacity are in good agreement with those obtained from the magnetocaloric effect. The MCE results obtained from the two different methods (magnetization and heat capacity) agree quite well with each other for all of the alloys in the series.

Research Organization:
Ames Lab., Ames, IA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
W-7405-ENG-82
OSTI ID:
754836
Report Number(s):
IS-T-1894; TRN: US0003357
Resource Relation:
Other Information: TH: Thesis (M.S.); Submitted to Iowa State Univ., Ames, IA (US); PBD: 1 Dec 1999
Country of Publication:
United States
Language:
English