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 Detalle_Publicacion

Magnetic disorder in TbAl2 nanoparticles

Abstract: The magnetic and thermal properties of TbAl2 nanosized alloys (diameters, 12 nm =D= 20 nm) obtained by high-energy milling are characterised by specific heat, magnetisation and neutron scattering. The specific heat shows that the ?-anomaly at Curie temperature vanishes when the milling time reaches 300 h and its field variation shows a broad peak around 70 K disclosing a disordered magnetic state. The thermal variation of magnetization follows a Bloch process with a decrease of the stiffness constant and a faster demagnetisation with a quadratic exponent instead of the bulk ordinary {T}^{3/2} dependence. The magnetic moment reduction in the nanosized alloys follows a 1/D dependence, remarking the role of disordered moment surface. The Rietveld analysis of the neutron diffraction patterns indicates a collinear ferromagnetic structure, with a reduction of the Tb-magnetic moment when decreasing the particle size. The temperature dependent overall magnetic signal of nanoparticles is derived from small-angle neutron scattering. A magnetic nanoparticle structure with an ordered ferromagnetic core and a disordered surface layer is proposed.

 Autoría: Rojas D., Fernández Barquín L., Sánchez Marcos J., Echevarria-Bonet C., Espeso J., Rodríguez Fernández J., Rodríguez Fernández L., Mathon M.,

 Fuente: Mater. Res. Express, Vol. 2, Num. 7, Art. Num. 075001 (2015)

Editorial: IOP Publishing

 Fecha de publicación: 01/07/2015

Nº de páginas: 9

Tipo de publicación: Artículo de Revista

 DOI: 10.1088/2053-1591/2/7/075001

ISSN: 2053-1591

Proyecto español: MAT2011–06542-c04

Url de la publicación: https://doi.org/10.1088/2053-1591/2/7/075001

Autores/as

DANIEL ROJAS PUPO

SÁNCHEZ MARCOS, J.

CRISTINA ECHEVARRIA BONET

LIDIA RODRIGUEZ FERNANDEZ

MATHON, M. H.