Juri Grin

Focus on complex metallic phases - Preface

1 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan Max-Planck-Institut for Chemical Physics of Solids, 01187 Dresden, Germany 3 Sciences de l’Ingéniérie, des Matériaux et des Procédés, Grenoble INP, CNRS, 28402 cedex, France E-mail: aptsai@tagen.tohoku. ac.jp The discovery of quasicrystal in 1982 has facilitated a revolution in crystallography and led to a paradigm shift in our understanding of the structure of ordered solids. The importance of the discovery was demonstrated by the fact that Professor Shechtman was awarded the 2011 Nobel Prize in Chemistry. More than 30 years since the discovery, the field has stimulated an enormous scientific activity ranging from pure mathematics to practical materials. The study of quasicrystal has spread to a new field, which covers complex metallic phases and/or quasicrystal approximants. In fact, it was only very recently that a better understanding of structure of quasicrystal has been attained and some applications in the field of complex metallic alloys have been tackled. The purpose of this issue is to present the current development in the basic and application-driven research on complex metallic phases, including the quasicrystals and their approximants. The issue contains 12 papers altogether, covering the new challenge of materials design for quasicrystals in several directions, such as structural materials, catalysts, thermoelectric materials and thermal rectification, new developments for related intermetallic compounds and the latest development on physical properties and surfaces. The papers are all written by excellent scientists in the field. Some of them are review articles, which will help readers understand the background of quasicrystals and the rest are original papers, which will show the state of the art of the field. We hope this issue will be helpful for scientists who want to learn the basic of quasicrystals or who want to know the recent progress on complex metallic phases in terms of materials science. Last but not the least, we are grateful to all authors for their contribution on this issue. Finally, we would like to thank Drs T Tanaka, T Hatano and T Yoshida at the editorial office of STAM for their generous help in progressing the review process.

Thermoelectric properties of Eu- and Na-substituted SnTe

Abstract Thermoelectric properties of spark-plasma-sintering prepared bulk materials Eu x Na y ▪ z Sn 1– x – y – z Te above room temperature were investigated. The implementation of Eu and Na into the SnTe lattice was monitored by refinement of lattice parameters as well as energy dispersive X-ray spectroscopy (EDXS). The binary SnTe achieved the highest ZT value of 0.63 at 786 K, and showed a hole concentration of 4.6×10 19 cm −3 at 300 K. In comparison with pristine SnTe, the samples containing Eu had lower carrier mobility but higher Hall carrier concentration. For Eu- and Na-substituted samples, the increased hole concentration was unfavorable for the improvement of thermoelectric properties.