Anomalous Transport and Thermal Properties of the Solid Solutions U_{1-x}Th_{x}Cu_{5}M (M = Al, Ga, In and Sn)

• Authors: R. Troć , V. Tran , D. Kaczorowski , A. Czopnik
• Languages of publication: EN

Abstracts

EN

UCu_{5}M-type compounds are moderate heavy fermion systems with an antiferromagnetic order below T_{N} = 18, 16-25, and 25 K for M = Al, (Ga, In), and In, respectively, and a ferrimagnetic order with T_{C} = 54 K for M = Sn. We present the results of magnetoresistance measurements as a function of temperature and applied magnetic field for the pure compounds and for their solid solutions containing Th, i.e. U_{1-x}Th_{x}Cu_{5}M. Only in the case of UCu_{5}In a substantial positive contribution to the magnetoresistance was observed at low temperatures, as for normal antiferromagnets. For the Al- and Sn-based alloys the magnetoresistance at low temperatures is negative, and its field variation proves the existence of Kondo-type interactions. On Th-substitution the magnetic phase transition is shifted to lower temperature and simultaneously the magnetoresistance becomes less negative. The field dependence of the magnetoresistance of these alloys can be well described by the Coqblin-Schrieffer model. Interestingly, the heat capacity measurements have revealed a general tendency to increase the linear coefficient γ with magnetic dilution of a given UCu_{5}M compound by Th-substitution. This feature reflects an enlargement of the effective mass of conduction electrons with the increase in both the unit cell volume and magnetic dilution. Such a tendency is also observed for the system UCu_{5}(In_{1-x}Ga_{x}), though the unit cell is here suppressed with increasing x. Thus, a similar physical picture is reached in all these systems but involving probably different mechanisms.

Keywords

EN

75.30.Mb; 72.15.Qm; 75.20.Hr

Discipline

• 72.15.Qm: Scattering mechanisms and Kondo effect(see also 75.20.Hr Local moments in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions in magnetic properties and materials)
• 75.30.Mb: Valence fluctuation, Kondo lattice, and heavy-fermion phenomena(see also 71.27.+a Strongly correlated electron systems, heavy fermions; for heavy-fermion superconductors, see 74.70.Tx)
• 75.20.Hr: Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions(for Kondo effect and scattering mechanisms in electronic conduction, see 72.15.Qm and 72.10.Fk)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2000
• Volume: 97
• Issue: 1
• Pages: 25-35

Dates

published

2000-01

Contributors

author

R. Troć

• W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław, Poland

author

V. Tran

• W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław, Poland

author

D. Kaczorowski

• W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław, Poland

author

A. Czopnik

• W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław, Poland

Identifiers

DOI

10.12693/APhysPolA.97.25