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Exploring the different degrees of magnetic disorder in TbxR1_xCu2 nanoparticle alloys

Abstract: Recently, potential technological interest has been revealed for the production of magnetocaloric alloys using Rare-Earth intermetallics. In this work, three series of TbxR1_xCu2 (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 TbCu2 orthorhombic Imma bulk crystalline structure. The analyses of the DC-magnetisation (MDC) and AC-susceptibility (cAC) show that three distinct degrees of disorder have been achieved by the combination of both the Tb3+replacement (dilution) and the nanoscaling. These disordered states are characterised by transitions which are evident to MDC, cAC and specific heat. There exists an evolution from the most ordered Superantiferromagnetic arrangement of the Tb0.5La0.5Cu2 NPs with Néel temperature, TN  27 K, and freezing temperature, Tf  7 K, to the less ordered weakly interacting Superparamagnetism of the Tb0.1Y0.9Cu2 nanoparticles (TN absent, and TB  3 K). The Super Spin Glass Tb0.5Gd0.5Cu2 nanoparticles (TN absent, and Tf  20 K) are considered an intermediate disposition in between those two extremes, according to their enhanced random-bond contribution to frustration.

 Authorship: Jefremovas E.M., Rodríguez M.d.l.F., Alonso J., Fernández J.R., Espeso J.I., Puente-Orench I., Rojas D.P., García-Prieto A., Fdez-Gubieda M.L., Fernández L.R., Barquín L.F.,

 Fuente: Nanomaterials, 2020, 10(11), 2148

 Publisher: MDPI

 Publication date: 28/10/2020

 No. of pages: 17

 Publication type: Article

 DOI: 10.3390/nano10112148

 ISSN: 2079-4991

 Spanish project: MAT2017-83631-C3-R

 Publication Url: https://doi.org/10.3390/nano10112148

Authorship

ELIZABETH MARTIN JEFREMOVAS

MARIA DE LA FUENTE RODRIGUEZ

PUENTE-ORENCH, INÉS

DANIEL ROJAS PUPO

GRACÍA-PRIETO, ANA

MARIA LUISA FERNANDEZ-GUBIEDA RUIZ

LIDIA RODRIGUEZ FERNANDEZ