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Title: Low-temperature transport, thermal, and optical properties of single-grain quasicrystals of icosahedral phases in the Y-Mg-Zn and Tb-Mg-Zn alloy systems

Low-temperature transport, thermal, and optical properties of single-grain quasicrystals of icosahedral phases in the Y-Mg-Zn and Tb-Mg-Zn alloy systems We present a comprehensive series of results of electrical transport (electrical conductivity, magnetoconductivity, Hall effect), thermal (specific heat), and optical (reflectivity) measurements in varying temperature ranges between 1.5 and 300 K on high-quality single-grain quasicrystals of icosahedral Y-Mg-Zn. This data set is augmented by the specific-heat and optical-reflectivity data obtained from a single-grain quasicrystal of icosahedral Tb-Mg-Zn. For Y-Mg-Zn, both the electrical conductivity {sigma}(T) and magnetoconductivity {delta}{sigma}(H) may be described by calculations considering quantum interference effects. A detailed comparison of the weak-localization contributions to {sigma}(T) and {delta}{sigma}(H) with our experimental data provides estimates of the inelastic and spin-orbit relaxation rates. The inelastic relaxation rate is found to be proportional to T{sup 3}. The dominant contributions to the optical conductivity {sigma}{sub 1}({omega}) spectrum, obtained from the reflectivity R({omega}) data in the frequency range between 16 and 9.7x10{sup 4} cm{sup -1}, are a strong Drude feature at low frequencies and a prominent absorption signal centered at approximately 6x10{sup 3} cm{sup -1}. A comparison of the spectral weight of the Drude contribution to {sigma}{sub 1}({omega}) with the magnitude of the linear-in-T term {gamma}T of the low-temperature specific heat C{sub p}(T) yields the itinerant charge-carrier density n{sub i}=7.62x10{sup 21} cm{sup -3} or 0.13 charge more » carriers per atom. The low n{sub i} value is corroborated by the results of the Hall effect measurements. For Tb-Mg-Zn, the optical conductivity {sigma}{sub 1}({omega}) spectrum reveals features similar to those of Y-Mg-Zn. The low-temperature specific heat C{sub p}(T) of Tb-Mg-Zn is strongly influenced by a spin-glass-type freezing of Tb moments and by crystal-electric-field effects. (c) 2000 The American Physical Society. « less
Authors: ; ; ; ; ; ; ; ;
Publication Date:
OSTI Identifier:OSTI ID: 20217103
Resource Type:Journal Article
Resource Relation:Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 62; Journal Issue: 1; Other Information: PBD: 1 Jul 2000
Country of Publication:United States
Language:English
Subject: 36 MATERIALS SCIENCE; YTTRIUM; TERBIUM ALLOYS; YTTRIUM ALLOYS; ZINC ALLOYS; MAGNESIUM ALLOYS; OPTICAL PROPERTIES; HALL EFFECT; CRYSTALS; SPECIFIC HEAT; REFLECTIVITY; MAGNETORESISTANCE; ELECTRIC CONDUCTIVITY; CHARGED-PARTICLE TRANSPORT; TEMPERATURE RANGE 0000-0013 K; TEMPERATURE RANGE 0013-0065 K; TEMPERATURE RANGE 0065-0273 K; SPIN GLASS STATE; CRYSTAL FIELD; ELECTRIC FIELDS; EXPERIMENTAL DATA