title: Effects of critical fluctuations and dimensionality on the jump in specific heat at the superconducting transition temperature: Application to YBa_{2}Cu_{3}O_{7-δ},Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}, and KOs_{2}O_{6} compounds.
abstract: We report on a study of the superconducting order parameter thermodynamic fluctuations in YBa_{2}Cu_{3}O_{7-δ},Bi_{2}Sr_{2}CaCu_{2}O_{8+δ}, and KOs_{2}O_{6} compounds. A nonperturbative technique within the framework of the renormalized Gaussian approach is proposed. The essential features are reported (analytically and numerically) through Ginzburg-Landau (GL) model-based calculations which take into account both the dimension and the microscopic parameters of the system. By presenting a self-consistent approach improvement on the GL theory, a technique for obtaining corrections to the asymptotic critical behavior in terms of nonuniversal parameters is developed. Therefore, corrections to the specific heat and the critical transition temperature for one-, two-, and three-dimensional samples are found taking into account the fact that fluctuations occur at all length scales as the critical point of a system is approached. The GL model in the free-field approximation and the 3D-XY model are suitable for describing the weak and strong fluctuation regimes respectively. However, with a modified quadratic coefficient, the renormalized GL model is able to explain certain experimental observations including the specific heat of complicated systems, such as the cup-rate superconductors and the β-pyrochlore oxides. It is clearly shown that the enhancement, suppression, or rounding of the specific heat jump of high-T_{c} cup-rate superconductors at the transition are indicative of the order parameter thermodynamic fluctuations according to the dimension and the nature of interactions.
authors.affiliation: Laboratory of Mechanics, Materials and Structures, Department of Physics, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon.|International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin.
authors.forename: R M
authors.initials: RM
authors.lastname: Keumo Tsiaze
authors.affiliation: International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin.
authors.forename: A V
authors.initials: AV
authors.lastname: Wirngo
authors.affiliation: International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin.|Laboratory of Research on Advanced Materials and Nonlinear Science (LaRAMaNS), Department of Physics, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
authors.forename: S E
authors.initials: SE
authors.lastname: Mkam Tchouobiap
authors.affiliation: Laboratory of Mechanics, Materials and Structures, Department of Physics, Faculty of Science, University of Yaoundé I, P.O. Box 812, Yaounde, Cameroon.|Mesoscopic and Multilayer Structure Laboratory, Department of Physics, Faculty of Science, University of Dschang, P.O. Box 479, Dschang, Cameroon.
authors.forename: A J
authors.initials: AJ
authors.lastname: Fotue
authors.affiliation: International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin.
authors.forename: E
authors.initials: E
authors.lastname: Baloïtcha
authors.affiliation: International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), University of Abomey-Calavi, 072 B.P. 50, Cotonou, Republic of Benin.
authors.forename: M N
authors.initials: MN
authors.lastname: Hounkonnou