Mesoscopic magnetic states in metallic alloys with strong electronic correlations : a percolative scenario for CeNi/sub 1-x/Cu/sub x/

• Autor(a) principal: Marcano, N.
• Data de Publicação: 2007
• Outros Autores: Gómez Sal, J.C., Espeso, José Ignacio, De Teresa, J.M., Algarabel, P.A., Paulsen, C., Iglesias, Jose Roberto
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRGS
• Texto Completo: http://hdl.handle.net/10183/99400
• topic: Ligas de cério; Ligas de cobre; Materiais ferromagnéticos; Aglomerados metálicos; Difração de nêutrons; Momentos magnéticos; Histerese; Transicao vitrea

We present evidence for the existence of magnetic clusters of approximately 20 Å in the strongly correlated alloy system CeNi1-xCux (0.7 ≤ x ≤ 0.2) based on small angle neutron scattering experiments as well as the occurrence of staircaselike hysteresis cycles at very low temperature (100 mK). An unusual feature is the observation of long-range ferromagnetic order below the cluster-glass transition without any indication of a sharp transition at a Curie temperature. These observations strongly support a phenomenological model where a percolative process connects both magnetic states. The model can account for all the puzzling data previously obtained in this system, providing a new perspective with regard to the magnetic ground state of other alloyed compounds with small magnetic moments or weak ferromagnetism with intrinsic disorder effects.