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Keywords:

  • geometrical frustration;
  • heavy fermion systems;
  • Kondo effect;
  • quantum criticality

Abstract

CePdAl crystallizes in the hexagonal ZrNiAl-type structure (space group equation image), where the magnetic Ce3+ ions form a network of equilateral triangles in the ab plane similar to the kagomé lattice. It is a well known antiferromagnetic heavy-fermion system with Néel temperature TN = 2.7 K. Magnetization and specific-heat measurements performed on CePd1 − xNixAl polycrystals show that the antiferromagnetic order in the system is suppressed by Ni substitution. TN is reduced to zero temperature at a Ni concentration x = 0.144. At high temperatures the magnetization data follow a Curie–Weiss law. The Weiss temperature equation image is negative with equation image increasing with x possibly due to the increasing Kondo effect. Indeed, the Kondo temperature increases with x as documented by an analysis of the specific heat and magnetic entropy of CePd1 − xNixAl for the samples with x = 0, 0.062, 0.097, and 0.144.