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 Detalle_Publicacion

Coexistence of ferromagnetism and spin glass state in YbNi2 nanoparticles

Abstract: We report changes on the magnetic behavior of the Heavy-Fermion ferromagnetic YbNi 2 alloy when reducing the size of the particles to the nanometer scale by high-energy ball milling. The milling process induces a reduction on the particle size of the bulk alloy down to 10 (2) nm and a lattice strain of 1.8 (2)%, for 30 h of milling time, as calculated from the X-ray diffraction data. The ferromagnetic transition at T C =10.5 K in the bulk alloy tends to disappear whereas other magnetic transitions arise at lower temperatures with the milling process. The AC magnetic susceptibility of the 30 h milled sample shows a frequency independent peak at 3 K, in a wide range of frequencies, consistent neither with superparamagnetic nor simple freezing of the magnetic moments, and as expected for a ferromagnetic behavior. However, from the specific heat measurements in the 30 h milled sample, a peak at 3.6 K is shifted respect to that observed in the AC magnetic susceptibility, as found in spin glasses. Additionally, the specific heat on nanometric samples show reduced magnetic contributions respect to the bulk alloy with ?c max around 0.45 J/molK. The results are explained by the influence of magnetic inhomogeneities and disorder of the alloys enhanced by the milling process in the ensemble of nanoparticles.

 Autoría: Rojas D., Fernández Barquín L., Espeso J., Rodríguez Fernández J., Alba Venero D., Gallastegui J., Castro G., Ivanshin V.,

 Fuente: Journal of Magnetism and Magnetic Materials 475 (2019) 264?270

Editorial: Elsevier

 Fecha de publicación: 01/04/2019

Nº de páginas: 7

Tipo de publicación: Artículo de Revista

 DOI: 10.1016/j.jmmm.2018.11.123

ISSN: 0304-8853,1873-4766

Url de la publicación: https://doi.org/10.1016/j.jmmm.2018.11.123

Autores/as

DANIEL ROJAS PUPO

DIEGO ALBA VENERO

GALLASTEGUI, J. A.

CASTRO, G. R.

IVANSHIN, V. A.