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Effect of Ca substitution on crystal structure and superconducting properties of ferromagnetic superconductor RuSr 2-xCa xGd 1.4Ce 0.6Cu 2O 10 -δ

Fallahi, S ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jmmm.2011.09.022
  3. Publisher: 2012
  4. Abstract:
  5. We have investigated the effect of Ca substitution for Sr site on structural, magnetic and superconducting properties of RuSr2 -x CaxGd1.4Ce0.6Cu2O10 -δ system. In this system, the magnetic coupling of RuO 2 and CuO 2 plays an important role in magnetic and superconducting states. X-ray diffraction analysis shows that all samples are single phase and the lattice parameters decrease continuously by increasing Ca content. The onset superconducting transition temperature is found to decrease with Ca substitution. As Ca content increases, rotation of the RuO 6 octahedron increases and RuO(1)Ru angle decreases. These variations strengthen the magnetic moments in the RuO 2 planes. The enhancement of weak ferromagnetic component and hole trapping by Ru magnetic moments in RuO 2 planes reduces the electrical conduction, and destroys the superconducting state in the system. Analysis of the resistivity data (ρ) based on the hoping conduction mechanism, indicates a variation of the hoping exponent (p) across the magnetic transition at T m. The hoping exponent p is not affected sharply by Ca concentration
  6. Keywords:
  7. Chemical pressure ; Hopping exponent ; Ruthenocuprate ; Ca substitution ; Chemical pressures ; Conduction Mechanism ; Electrical conduction ; Ferromagnetic component ; Ferromagnetic superconductors ; Hole trapping ; Hopping exponent ; Magnetic transitions ; Resistivity data ; Rutheno-cuprates ; Single phase ; Superconducting properties ; Superconducting state ; Calcium ; Crystal structure ; Ferromagnetic materials ; Ferromagnetism ; Gadolinium ; Magnetic couplings ; Magnetic moments ; Magnetism ; Ruthenium alloys ; Ruthenium compounds ; Superconducting materials ; Superconducting transition temperature ; X ray diffraction analysis ; Superconductivity
  8. Source: Journal of Magnetism and Magnetic Materials ; Volume 324, Issue 6 , 2012 , Pages 949-954 ; 03048853 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0304885311006925