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Local‐moment and itinerant antiferromagnetism in the heavy‐fermion system Ce(Cu 1−x Ni x ) 2 Ge 2
Author(s) -
Loidl A.,
Krimmel A.,
Knorr K.,
Sparn G.,
Lang M.,
Geibel C.,
Horn S.,
Grauel A.,
Steglich F.,
Welslau B.,
Grewe N.,
Nakotte H.,
de Boer F. R.,
Murani A. P.
Publication year - 1992
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19925040203
Subject(s) - condensed matter physics , antiferromagnetism , magnetization , magnetism , physics , electrical resistivity and conductivity , magnetic moment , seebeck coefficient , phase diagram , neutron scattering , scattering , materials science , phase (matter) , magnetic field , quantum mechanics , optics
Elastic and inelastic neutron‐scattering studies on the system Ce(Cu 1−x Ni x ) 2 Ge 2 are reported. These measurements are complemented by measurements of the magnetic susceptibility, high‐field magnetization, heat capacity, thermal expansion, electrical resistivity and thermopower. The results reveal an interesting T‐x phase diagram consisting of two different antiferromagnetic phases for x < 0.2 and 0.2 < x < 0.75, respectively, and a heavy‐Fermi‐liquid regime at higher Ni concentrations. The experimental results are interpreted in terms of an alloying‐induced transition from local‐moment to itinerant heavy‐fermion magnetism. Fingerprints of this latter phase are a strongly reduced ordered moment and a short incommensurate ordering wave vector, in accord with theoretical predictions. A surprisingly good agreement between theory and experiment is found for x > 0.5. Further experimental evidence for different types of antiferromagnetic ordering derives from a line‐shape analysis of the quasielastic neutron‐scattering intensity, from magnetization and thermopower experiments.