Structural and magnetic properties of the half-ferromagnetic Co2+x+yMn1-xAl1-y alloys

• Autor(a) principal: Paduani,C.
• Data de Publicação: 2007
• Outros Autores: Migliavacca,A., Krause,J.C., Ardisson,J.D., Yoshida,M.I.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Physics
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332007000800015
• topic: Heusler alloys; Cobalt; Manganese; Aluminum; Half-ferromagnetic materials

Co2+x+yMn1-xAl1-y intermetallic compounds have been prepared by arc melting and studied with X-ray diffraction and magnetization measurements to ascertain the effect of deviations of composition from the stoichiometry on the ferromagnetism of this system. Hysteresis loops registered at room temperature show a soft ferromagnetic behavior in excess Co. In off-stoichiometric alloys the saturation magnetization is lower than in Co2MnAl, whereas the Curie temperature T C is higher in all the studied alloys. T C varies substantially with variations in composition and increases with the Mn content. In the source of this behavior a volume effect is inferred which is expected to lead to strengthened ferromagnetic exchanges.