Mass enhancement, correlations, and strong coupling superconductivity in the beta-pyrochlore KOs2O6

To assess electron correlation and electron-phonon coupling in the recently discovered beta-pyrochlores KOs2O6 and RbOs2O6, we have performed specific heat measurements in magnetic fields up to 14 T. We present data from high quality single crystalline KOs2O6, showing that KOs2O6 is a strong coupling superconductor with a coupling parameter lambda_ep \approx 1.0 to 1.6 (RbOs2O6: lambda_ep \approx 1). The estimated Sommerfeld coefficient of KOs2O6, gamma=76 to 110 mJ/(mol K^2), is twice that of RbOs2O6 [gamma=44 mJ/(mol K^2)]. Using strong-coupling corrections, we extract useful thermodynamic parameters of KOs2O6. Quantifying lambda_ep allows us to determine the mass enhancement over the calculated band electronic density of states. A significant contribution in addition to the electron-phonon term of lambda_c=1.7 to 4.3 is deduced. In an effort to understand the origin of the enhancement mechanism, we also investigate an unusual energetically low-lying phonon. There are three phonon modes per RbOs2O6, suggestive of the phonon source being the rattling motion of the alkali ion. This dynamic instability of the alkali ions causes large scattering of the charge carriers which shows up in an unusual temperature dependence of the electrical resistivity.Comment: Accepted for publication in PR

The impact of information and communication technology and internal market orientation blending on organisational performance in small and medium enterprises

Purpose: The present study examines the concept of internal market orientation (IMO) and its effects on organisational performance comprising job satisfaction and employees’ loyalty in the small and medium enterprises (SMEs) research context. Rooted in administrative theory, human relations theory, conventional theories of IMO, and internal marketing, this study develops a novel iIMO theoretical framework which evinces the proliferation of ICTs in SMEs. Design/methodology/approach: The proposed concept was empirically investigated by means of surveying 316 SME employees with the application of a multi-stage sampling procedure. Findings: Research findings confirmed the viability of the ICT-supported iIMO framework, its positive effects on SMEs’ organisational performance, and exhibited ample empirical evidence for the proficiency of the iIMO concept and its suitability for operationalisation by SMEs. Originality/value: This study introduces ICTs as a novel IMO dimension which considers the undergoing holistic digitalisation of businesses. In addition, the present research posits the plausibility and confirms the benefits that arise following iIMO implementation in SMEs

Synthesis of superconducting pyrochlore RbOs2O6

RbOs2O6, the third superconducting pyrochlore oxide (known so far), has been synthesized by encapsulation and by high pressure techniques. Suitable post chemical treatment of the as-prepared sample allowed us to eliminate the impurity phases. Bulk superconductivity with Tc=6.4 K was observed in magnetisation and specific heat measurements. The transition temperature of RbOs2O6 was found to be the same for both preparation methods. Structural investigations showed that Rb atoms occupy the 8b site in the pyrochlore lattice with a lattice parameter of 10.1137(1) A.Comment: 12 pages, 5 figures, correction to one author name and Figure