Pressure-induced superconductivity

Pure barium is a silvery-white metal, although contamination with nitrogen produces a yellowish color. The metal is relatively soft and ductile and may be worked readily. It is fairly volatile (though less so than magnesium), and this property is used to advantage in commercial production. Barium has a bcc crystal stmcture at atmospheric pressure, but undergoes soHd-state phase transformations at high pressures (2,3). Because of such transformations, barium exhibits pressure-induced superconductivity at sufftciendy low temperatures (4,5). 

Fig. 2 Pressure-induced superconductivity in TTF[Ni(dmit)2]2- Redrawn after [40]...

Yokota T, Takeshita N, Shimizu K, Amaya K, Onodera A, Shirotani I, Endo S (1996) Pressure-induced superconductivity of iodanil. Czech J Phys 46 817-818... 

Amaya K, Shimizu K, Takeshita N, Eremets MI, Kobayashi TC, Endo S (1998) Observation of pressure-induced superconductivity in the megabar region. J Phys Condens Matter 10 11179-11190... 

Takimiya K, Kodani M, NiUiara N, Aso Y, Otsubo T, Bando Y, Kawamoto T, Mori T (2004) Pressure-induced superconductivity in (MDT-TS)(Aul2)o.44i [MDT-TS = 5H-2-(l,3-diselenol-2-ylidene)-l,3,4,6-tetrathiapentalene] anew organic superconductor possessing an incommensurate anion lattice. Chem Mater 16 5120-5123... 

Shimizu Y, Kasahara H, Furuta T, Miyagawa K, Kanoda K, Maesato M, Saito G (2010) Pressure-induced superconductivity and Mott transition in spin-liquid k-(ET)2Cu2(CN)3 probed by NMR. Phys Rev B 81 224508/1-5... 

R 704 N. Fujiwara, N. Mori, M. Uedoko, T. Matsumoto, N. Motoyama and S. Uchida, New Development in NMR Measurement Technology Research on Pressure Induced Superconductivity under 4Gpa Class Pressure , JAERI - Conf, 2004,2003-21,199... 

Pressure-induced superconductivity in CePd2Si2 and CeNi2Ge2 The compounds CeNi2Gc2 and CePd2Si2 offer the possibility for studies of the antiferromagnetic instability in a heavy-fermion system. In the vicinity of the quantum critical point, non-... 

It was found that the Tc of La, already fairly high at normal pressure, increases strongly if the metal is compressed by external pressure (Smith and Gardner, 1966). Subsequently, Y, Lu and Sc have also been studied for superconductivity. The experiments led to the discovery of pressure-induced superconductivity in Y and Lu. At the highest pressures reported below (150-200kbar) the volume compression AVIV of La, Y and Lu is of the order of... 

Fig. 10.1. Left side of the periodic table. Instead of La, Lu has been placed below Sc and Y (Hamilton, 1965). The values below the symbols of the elements are the superconducting transition temperatures in degrees K. Recently, pressure-induced superconductivity has also been observed in a new high pressure phase of scandium (cf. section 6).

One way to induce superconductivity in a molecular metal has proven to be the application of pressure which often prevents or removes the... 

As in polycrystalline pressed at-(BEDT-TTF)2l3, in pressed samples of Pp-(BEDT-l lF)2l3 a pressure-induced structural phase transition plays an important role. As a consequence of the structural phase transition in pp-(BEDT-TTF)2l3, the superconducting transition temperature is increas. This behavior re-emphasizes that organic superconductors might also be of interest for industrial applications, since polyciystalline materials are easier to use than single crystals. In addition, the discovery of bulk superconductivity in large pressed samples of crystallites of organic metals, of the typical diameter of 1 p.m and below, indicates that the observation of superconductivity in conducting polymers should be possible as well. 

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