MATERIALS TRANSACTIONS
Online ISSN : 1347-5320
Print ISSN : 1345-9678
Metal-Insulator Transition in the Amorphous CexSi100-x (4≤ x≤ 83) Heavy Fermion System
Tetsushi BiwaMasaaki YuiTsunehiro TakeuchiUichiro Mizutani
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2001 Volume 42 Issue 6 Pages 939-950

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Abstract

The electronic structure, magnetic properties and electron transport properties have been studied on amorphous CexSi100−x (4≤x≤83) alloys in comparison with non-magnetic amorphous LaxSi100−x (11≤x≤63) and TixSi100−x (6≤x≤41) alloys with a particular emphasis on the formation of the pseudogap at the Fermi level and its effect on the electron transport upon approaching the metal-insulator transition in the heavy fermion system. It is shown that the interaction between conduction electrons and localized moments leads to an anomalous enhancement in the temperature dependence of the measured resistivity below 10 K . We also revealed that the amorphous CexSi100−x alloy system crosses the metal-insulator transition at about 12 at%Ce and that the marginally metallic Ce15Si85 alloy has the resistivity of 1500 \\microΩcm comparable to those in the non-magnetic reference systems but a large electronic specific heat coefficient γ of 22 mJ/mol·K2, which is 50 times as large as the value of 0.4 mJ/mol·K2 for the marginally metallic Ti13Si87 alloy. The set of (ρ300 K, γexp) data fall on an extremely small diffusion constant line in the ρ-γ diagram. This unique behavior is attributed to the existence of Ce-4f electrons at the Fermi level, which give rise to a large value of γ but are localized and immobile even in the metallic regime.

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© 2001 The Japan Institute of Metals and Materials
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