| Autor: |
Jefremovas, Elizabeth M., Rodríguez, María de la Fuente, Alonso, Javier, Fernández, Jesús Rodríguez, Espeso, José Ignacio, Puente-Orench, Inés, Rojas, Daniel P., García-Prieto, Ana, Fdez-Gubieda, María Luisa, Fernández, Lidia Rodríguez, Barquín, Luis Fernández |
| Předmět: |
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| Zdroj: |
Nanomaterials (2079-4991); Nov2020, Vol. 10 Issue 11, p2148-2148, 1p |
| Abstrakt: |
Recently, potential technological interest has been revealed for the production of magnetocaloric alloys using Rare-Earth intermetallics. In this work, three series of Tb x R 1 − x Cu 2 (R ≡ Gd, La, Y) alloys have been produced in bulk and nanoparticle sizes via arc melting and high energy ball milling. Rietveld refinements of the X-ray and Neutron diffraction patterns indicate that the crystalline structure in all alloys is consistent with TbCu 2 orthorhombic I m m a bulk crystalline structure. The analyses of the DC-magnetisation ( M D C ) and AC-susceptibility ( χ A C ) show that three distinct degrees of disorder have been achieved by the combination of both the Tb 3 + replacement (dilution) and the nanoscaling. These disordered states are characterised by transitions which are evident to M D C , χ A C and specific heat. There exists an evolution from the most ordered Superantiferromagnetic arrangement of the Tb 0.5 La 0.5 Cu 2 NPs with Néel temperature, T N ∼ 27 K, and freezing temperature, T f ∼ 7 K, to the less ordered weakly interacting Superparamagnetism of the Tb 0.1 Y 0.9 Cu 2 nanoparticles ( T N absent, and T B ∼ 3 K). The Super Spin Glass Tb 0.5 Gd 0.5 Cu 2 nanoparticles ( T N absent, and T f ∼ 20 K) are considered an intermediate disposition in between those two extremes, according to their enhanced random-bond contribution to frustration. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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