Available from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel C 145990 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Echevarria-Bonet, C.

Espeso, J.I.

Fernández Barquín, L.

Mathon, M.H.

Rodríguez Fernández, J.

Rodríguez Fernández, L.

Rojas Pupo, Daniel

Sánchez Marcos, J.

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

Archivo Digital UPM

Magnetic disorder in TbAl2 nanoparticles

Servicio de Coordinación de Bibliotecas de la Universidad Politécnica de Madrid

Meffert, Heribert

Hafner, Kay

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