8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P1.44Fri 911:10-14:00Medium range fluctuation in liquid pseudo-binarymixture between non-superionic AgCl and superionic AgIHiroki Ueno, 1 Yukinobu Kawakita, 2 Shuta Tahara, 3 Koji Ohara, 4 HironoriShimakura, 5 Rosantha Kumara, 5 Akinori Yasunaga, 5 Yuiko Wakisaka, 5 ShunsukeOhba, 5 Jyunpei Yahiro, 5 Masanori Inui, 6 Yukio Kajihara, 6 Shinji Kohara, 4 andShin’ichi Takeda 51 Kyushu University, 6-10-1, Hakozaki, Higashi-Ku, 812-8581, Fukuoka, Japan2 Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, Japan3 University of the Ryukyus, Nishihara, Nakagusuku, Okinawa, Japan4 JASRI/SPring-8, Sayo-cho, Sayo-gun, Hyogo, Japan5 Kyushu University, Fukuoka, Japan6 Hiroshima University, Higashi-Hiroshima, Hiroshima, JapanAgI is known as a typical superionic conductor called as α-AgI at high temperature. In this phase,Ag+ ions migrate as charge carrier into the interstices of the b.c.c. sub lattice that I- ions form andfavor a center of an anion-tetrahedral configuration. On the other hand, AgCl is rock-salt structurewhere it doesn’t exhibit superionic behavior. It has been revealed that such local ordering on thesolid structures retain even in the liquid phases by previous studies about liquid silver halides. Especiallyin liquid AgI, Ag+ ions form chain like conformation which strongly implies ”caterpillar”motion, proposed for Ag based superionic conductors by Yokoyama. The pseudo-binary mixturebetween non-superionic AgCl and superionic AgI shows eutectic phase diagram and has theminimum melting point of 259 ◦ C at (AgCl)0.43(AgI)0.57. In liquid (AgCl)0.43(AgI)0.57, soundabsorption which is related to viscosity exhibits anomalous temperature dependence that it showsrelatively low constant value near the melting point, and steeply rises with increasing temperaturefrom 400 ◦ C to reach the maximum at around 550 ◦ C near melting temperature of AgI and thendecreases with further increase of temperature. To focus medium-range fluctuations around 0.1- 1.2 å −1 in static liquid structure in relation to anomalous alternation of dynamical property forliquid (AgCl)0.43(AgI)0.57, we measured precise temperature dependence in a range from 280 to820 ◦ C of small angle x-ray scattering using relative high-energy incident X-ray of 61.7keV. Theexperiments were carried out using an imaging plate (IP) installed at BL04B2 in SPring-8, Japan.The intensity of scattered X-ray shows a monotonous increase with increasing temperature. However,in the temperature range from 600 to 700 ◦ C just beyond the sound absorption maximum, anadditional increase of the intensity in a low Q region was observed.44