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Cuprate spin ladder crystals grown by floating zone method under elevated oxygen pressure

Guochu Deng 1,2Kazimierz Conder 1Ekaterina Pomjakushina 1

1. Paul Scherrer Institut (PSI), WLGA, Villigen PSI 5232, Switzerland
2. Bragg Institute,, New Illawarra Road, Lucas Height, New South Wales 2233, Austria

Abstract

Quasi-one-dimensional cuprates Sr14-xCaxCu24O41, have attracted much attention, mainly because they represent an unique class of superconducting copper oxides with a non-square copper oxide layers. For the first time superconductivity with TC≈12 K was observed for highly Ca-doped samples (x≈13.6) under high hydrostatic pressure of 3-4.5GPa [1]. In spite this system is investigated since years it looks that many discrepancies could be clarified if high quality, large size, highly Ca doped single crystals would be available. Such crystals with Ca-content close to x=12 were grown by Travelling Solvent Floating Zone (TSFZ) method under oxygen pressure of 12bar [2], already slightly exceeding a pressure limit of the commercially available mirror furnaces. In this work for the crystal growth of Sr14-xCaxCu24O41 with high Ca content (x>12), we have modified the mirror furnace to provide a stable crystal growth at oxygen pressure up to 35bar [3]. The grown crystals were found to be of high quality as studied by microscopy, micro X-ray fluorescence elemental analysis and X-ray diffraction. Incommensurate crystal structures of the series Sr14-xCaxCu24O41 (x=3, 7, 11, 12.2) were characterized by powder neutron scattering method. The Ca doping effects on the lattice parameters, atomic displacement, Cu-O distances, Cu-O bond angles and Cu bond valence sum were studied [4]. Measurements of superconducting and magnetic properties under hydrostatic [5] and uniaxial pressure will be also presented.

[1] M. Uehara et al., J Phys Soc Jpn., 65 (1996) 2764

[2] S. Vanishri et al., J. Cryst. Growth, 311 (2009) 3830

[3] G. Deng et al., J. Cryst. Growth, 327 (2011) 182

[4] G. Deng et al., Phys. Rev. B, 84 (2011) 144111

[5] A. Hisada et al., Phys. Rev. B, submitted

 

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Related papers

Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 6, by Kazimierz Conder
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-03-25 15:16
Revised:   2013-03-25 15:16