SUPERCONDUCTIVITY IN Y(BAxSR1−x)CUO SYSTEM

Abstract

A number of samples with the nominal formula Y 0.4( Ba x Sr 1−x)0.6 Cu O 3, Y 0.5( Ba x Sr 1−x)0.5 CuO 3 and Y 1.2 ( Ba x Sr 1−x)0.8 CuO 4 have been made. It is found that for x=0 the samples show no superconductivity but for x>0.008 samples do show superconductivity, and for x=0.008, 0.005 the samples have high normal resistivity and no resistive transition but show diamagnetism at about 70k. The structure analysis find a smaller distortion in the the sample Y 0.5( Ba 0.01 Sr 0.99)0.5 CuO 3 than that in YBa 2 Cu 3 O 9−y. The relation between superconductivity and the ionic radius is discussed.

Matrix generalizations of integrable systems with Lax integro-differential representations

“…The (2+1)-dimensional extension of the k-cKP hierarchy has been rediscovered more recently in [33], also see [34,40] for further investigations. The authors of [33] and [34] considered the (2+1)-dimensional k-cKP and (2+1)-dimensional k-cmKP hierarchies with two operators of the Lax pair having different orders of differentiation with respect to x. This excludes, for example, (2+1)-dimensional vector generalizations of the Yajima-Oikawa (17) and Drinfeld-Sokolov-Wilson equation [41][42][43]:…”

“…In [31,32], exact solutions for some representatives of the (2+1)dimensional k-cKP hierarchy were obtained by dressing binary transformations. (2+1)-dimensional extensions of k-cKP and k-cmKP and their dressings with the help of differential transformations were investigated in [33,34]. The (2+1)-dimensional k-cKP hierarchy in particular contains the DS-III system and a (2+1)dimensional extension of the mKdV equation.…”

Modified entropic gravity revisited

“…[27][28][29][30][31][32][33][34][35] explored the possibility of entropic gravity with more complicated equipartition relations. Exceptions include changing more than one ingredients [36] or considering corrections from the uncertainty principle [37][38][39].…”

Effects of string cloud on Gauss-Bonnet holographic superconductors

“…The dual gravitational description of s-wave superconductors was first proposed by Hartnoll et al at which a phase transition from a black hole with no hair to one with scalar hair is interpreted as the (normal) conductor/superconducting phase transition in the dual field theory [3,4]. Following this work, the investigations of holographic superconductors in the framework of Einstein gravity have attracted a lot of attention [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23].…”