Agradecimentos: This work was supported partially by the EC under ALFA II network No II0147FI. The LNLS at Campinas, Brazil, is gratefully acknowledged for financial assistance in the framework of the project XRD 884/01. J C Denardin is acknowledged for his help in the VSM magnetic measurements. The Program CAPES/MES (029-07) COOPERACION BRASIL-CUBA is also acknowledged for partial financial support. The authors would also like to thank the Brazilian agencies CNPq and FAPERJ. L A S de Oliveira thanks CAPES for the doctorate fellowship Ver menos

Abstract: The structure of annealed Sm(Co0.6Cu0.4)(5) compounds, prepared with different Sm excess content, has been investigated by means of high resolution x-ray diffraction and scanning electron microscopy. The samples were also magnetically characterized by thermomagnetic analysis and M versus H curves at room temperature. Increasing Sm excess improves the compositional order of the 1 : 5 phase. The coercivity (H-C) and the Curie temperature (T-C) are both changed as a function of Sm excess content. The decrease in the structural defects density, resulting from the compositional order, is responsible for the observed magnetic behaviour Ver menos