Magnetocaloric Effect of Micro- and Nanoparticles of Gd5Si4
Materials exhibiting a large magnetocaloric effect (MCE) at or near room temperature are critical for solid-state refrigeration applications. The MCE is described by a change in entropy (Δ S M ) and/or temperature (Δ T ad ) of a material in response to a change in applied magnetic field. Ball milled...
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Veröffentlicht in: | JOM (1989) 2019-09, Vol.71 (9), p.3159-3163 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Materials exhibiting a large magnetocaloric effect (MCE) at or near room temperature are critical for solid-state refrigeration applications. The MCE is described by a change in entropy (Δ
S
M
) and/or temperature (Δ
T
ad
) of a material in response to a change in applied magnetic field. Ball milled materials generally exhibit smaller Δ
S
M
values compared to bulk; however, milling broadens the effect, potentially increasing the relative cooling power (RCP). The as-cast Gd
5
Si
4
is an attractive option due to its magnetic transition at 340 K and associated MCE. Investigation of effect of particles size and transition temperature in the binary material, Gd
5
Si
4
, can lead to development of functionally graded bulk material with higher MCE and RCP than the traditional bulk materials. A two-step ball-milling process, in which coarse powder of Gd
5
Si
4
was first milled with poly(ethylene glycol) followed by milling in heptane was used to produce fine particles of Gd
5
Si
4
that showed a broad distribution in particle size. Magnetic measurement on the milled sample obtained after washing with water show a decrease in Curie temperature and significant broadening of the magnetic transition. Compared to bulk Gd
5
Si
4
, the maximum MCE of the milled samples is also reduced and shifted down by close to 30 K, but the MCE remains substantial over a broader temperature range. The RCP of both milled samples increased 75% from the bulk material. |
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ISSN: | 1047-4838 1543-1851 |
DOI: | 10.1007/s11837-019-03626-1 |