Magnetic disorder in TbAl2 nanoparticles

Rojas Pupo, Daniel and Fernández Barquín, L. and Sánchez Marcos, J. and Echevarria-Bonet, C. and Espeso, J.I. and Rodríguez Fernández, J. and Rodríguez Fernández, L. and Mathon, M.H. (2015). Magnetic disorder in TbAl2 nanoparticles. "Materials Research Express", v. 2 (n. 7); pp. 11-19. ISSN 2053-1591.


Title: Magnetic disorder in TbAl2 nanoparticles
  • Rojas Pupo, Daniel
  • Fernández Barquín, L.
  • Sánchez Marcos, J.
  • Echevarria-Bonet, C.
  • Espeso, J.I.
  • Rodríguez Fernández, J.
  • Rodríguez Fernández, L.
  • Mathon, M.H.
Item Type: Article
Título de Revista/Publicación: Materials Research Express
Date: July 2015
Volume: 2
Faculty: E.T.S. Arquitectura (UPM)
Department: Estructuras y Física de Edificación
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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The magnetic and thermal properties of TbAl2 nanosized alloys (diameters, 12 nm $\leqslant D\leqslant $ 20 nm) obtained by high-energy milling are characterised by specific heat, magnetisation and neutron scattering. The specific heat shows that the λ-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.

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Item ID: 40917
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Deposited by: Memoria Investigacion
Deposited on: 14 Jun 2016 08:10
Last Modified: 14 Jun 2016 08:10
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