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Preservation of large low temperature magnetocaloric effect in metamagnetic intermetallic compounds RCu2 (R = Gd, Tb, Dy, Ho and Er) upon rapid solidification
R. Rajivgandhi,
Published in Elsevier Ltd
2020
Volume: 815
   
Abstract
In this work, magnetic and magnetocaloric properties of melt-spun RCu2 (R = Gd, Tb, Dy, Ho and Er) compounds have been studied. The melt-spun samples have formed in the same orthorhombic crystal structure (space group Imma, no. 74) as that of the arc-melted samples but with a development of crystallographic texture and micron-size grains. The melt-spun ribbons of RCu2 (R = Gd, Tb, Dy, Ho and Er) order antiferromagnetically at 43 K, 51 K, 28 K, 10 K and 11 K (TN) respectively. The ordering temperatures are almost the same as that of the arc-melted samples. The RCu2 compounds show one or more field induced transitions below TN. Therefore, a normal magnetocaloric effect is observed in these compounds when the magnetic field change is larger than the metamagnetic critical field and inverse magnetocaloric effect is observed for smaller field changes. The microgranularity does not seem to smear out the metamagnetic transition. The maximum of isothermal magnetic entropy change, ΔSmmax, is about −2.1 Jkg−1K−1, -5.5 Jkg−1K−1, -5.2 Jkg−1K−1, -17.2 Jkg−1K−1 and -11.7 Jkg−1K−1 respectively for the melt-spun RCu2 (R = Gd, Tb, Dy, Ho and Er) samples for 50 kOe field change. The refrigeration capacity is found to be 40 Jkg-1, 160 Jkg-1, 166 Jkg-1, 230 Jkg-1 and 207 Jkg-1 respectively, for the above samples. These values are nearly the same as that of the arc-melted counterparts. Thus the large magnetocaloric effect in the temperature range of 10 K–70 K make these melt-spun RCu2 samples potential materials for low temperature refrigeration applications. The results also ascertain melt-spinning process as an alternate technique for the production of magnetocaloric alloys and intermetallics. © 2019 Elsevier B.V.
About the journal
JournalData powered by TypesetJournal of Alloys and Compounds
PublisherData powered by TypesetElsevier Ltd
ISSN09258388
Open AccessNo
Concepts (19)
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    Crystal structure
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    Erbium compounds
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    Holmium compounds
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    INTERMETALLICS
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    Melt spinning
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    Rapid solidification
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    Rare earths
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    Refrigeration
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    Temperature
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    Textures
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    Crystallographic textures
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    FIELD-INDUCED TRANSITIONS
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    Isothermal magnetic entropy change
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    LOW TEMPERATURE REFRIGERATION
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    Magnetocaloric properties
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    Metamagnetic transitions
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    ORTHORHOMBIC CRYSTAL STRUCTURES
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    Rare earth intermetallics
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    Magnetocaloric effects