Results of the transport properties of the YbNi1−xCuxAl (x = 0, 0.2, 0.5, 0.8 and 1.0) series of alloys are reported. The previous analysis of X-ray diffraction patterns indicates that all compounds crystallize in the hexagonal ZrNiAl structure with a linear behavior of the unit cell volume as a function of the Cu concentration (x). This is not found in the unit cell parameters, showing a discontinuity between x = 0.5 and 0.8. Such discontinuities affect the behavior of the electrical resistivity, in which the position of the minimum temperature changes from 95 K to 175 K, and a rise in the low temperature slope in the magnetic contribution (with -lnT dependence) from 21 μΩcm to 212 μΩcm is observed. In addition, the electronic coefficient of the specific heat increases almost twofold from 125 mJ/mol·K2 (x = 0.5) to 246 mJ/mol·K2 (x = 0.8). These changes are attributed to the variation of the distance between Yb and transition metals (Ni and Cu) along the series and the different electronic properties of the transition metals (Ni and Cu).

Gostaria de agradecer, em especial, ao profesor Flávio César Guimarães Gandra, pela dedicação e eficiência com que me orientou ao longo destes dois anos.Ao professor Sergio Gama e Adelino pela preparação das amostras, analise metalográfica e microsonda eletrônica.Ao professor Lisandro Pavié Cardoso , Wanderson e Alfredo pelo raios -x das amostras.Aos amigos que trabalham, ou trabalharam no Grupo de Metais e ligas: Vinicius , Alexandre e Antonio, pela ajuda nas montagens experimentais, e pelas discussões e sugestões.Este trabalho foi realizado com suporte financeiro da FAPESP, FAEP-UNICAMP, CNPq e CAPES, a través de projetos de pesquisa e concessão de bolsas.

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