Single crystal growth and structure analysis of type-I (Na/Sr)-(Ga/Si) quaternary clathrates

Hironao Urushiyama; Haruhiko Morito; Hisanori Yamane

doi:10.1039/c9ra01489f

Single crystal growth and structure analysis of type-I (Na/Sr)-(Ga/Si) quaternary clathrates

RSC Adv. 2019 May 9;9(26):14586-14591. doi: 10.1039/c9ra01489f.

Authors

Hironao Urushiyama^{1

2}, Haruhiko Morito³, Hisanori Yamane¹

Affiliations

¹ Institute of Multidisciplinary Research for Advanced Materials, Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan.
² Department of Metallurgy, Materials Science and Materials Processing, Graduate School of Engineering, Tohoku University 6-6-04 Aramaki Aza Aoba, Aoba-ku Sendai 980-8579 Japan.
³ Institute for Materials Research, Tohoku University 2-1-1 Katahira, Aoba-ku Sendai 980-8577 Japan [email protected].

Abstract

Single crystals of (Na/Sr)-(Ga/Si) quaternary type-I clathrates, Na_8-y Sr _y Ga _x Si_46-x , were synthesized by evaporating Na from a mixture of Na-Sr-Ga-Si-Sn in a 6 : 0.5 : 1 : 2 : 1 molar ratio at 773 K for 12 h in an Ar atmosphere. Electron-probe microanalysis and single-crystal X-ray diffraction revealed that three crystals from the same product were Na_8-y Sr _y Ga _x Si_46-x with x and y values of 7.6, 2.96; 8.4, 3.80; and 9.1, 4.08. It was also shown that increasing the Sr and Ga contents increased the electrical resistivity of the crystal from 0.34 to 1.05 mΩ cm at 300 K.