A. Maisuradze

Oxygen Isotope Effects on the Superconducting Transition and Magnetic States Within the Phase Diagram of Y1-xPrxBa2Cu3O7-δ

R. Khasanov, A. Shengelaya, 2 D. Di Castro, 3 E. Morenzoni, A. Maisuradze, I.M. Savić, K. Conder, E. Pomjakushina, 7 and H. Keller Physik-Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland Physics Institute of Tbilisi State University, Chavchavadze 3, GE-0128 Tbilisi, Georgia ”Coherentia” CNR-INFM and Dipartimento di Fisica, Universita’ di Roma ”La Sapienza”, P.le A. Moro 2, I-00185 Roma, Italy Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland Faculty of Physics, University of Belgrade, 11001 Belgrade, Serbia and Montenegro Laboratory for Developments and Methods, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland Laboratory for Neutron Scattering, Paul Scherrer Institute & ETH Zurich,CH-5232 Villigen PSI, Switzerland Oxygen isotope (O/O) effects (OIE’s) on the superconducting transition (Tc), the spinglass ordering (Tg), and the antiferromagnetic ordering (TN) temperatures were studied for Y1−xPrxBa2Cu3O7−δ as a function of Pr content (0.0 ≤ x ≤ 1.0). The OIE on Tc increases with increasing x up to x ≈ 0.55, where superconductivity disappears. For decreasing x the OIE’s on TN and Tg increase down to x ≈ 0.7 where antiferromagnetic order and down to x ≈ 0.3 where spin-glass behavior vanish, respectively. The OIE’s on Tg and TN are found to have opposite signs as compared to the OIE on Tc. All OIE’s are suggested to arise from the isotope dependent mobility (kinetic energy) of the charge carriers.

Mixed order parameter symmetries in cuprate superconductors

The recent observation of an inflection point in the temperature dependence of the in-plane magnetic field dependence (λab) is investigated within a two-band model with coupled order parameters of different symmetries. While the dominant order parameter has d-wave symmetry, the smaller one is of s-wave symmetry. Superconductivity is robust in the d-wave channel and induced via interband interactions in the s-wave subsystem.

Pressure effects on the transition temperature and the magnetic field penetration depth in the pyrochlore superconductor RbOs2O6.

Magnetization measurements under hydrostatic pressure up to 8 kbar in the pyrochlore superconductor RbOs2O6 (T(c) approximately or equal 6.3 K at p=0) were carried out. A positive pressure effect on T(c) with dT(c)/dp=0.090(3) K/kbar was observed, whereas no pressure effect on the magnetic penetration depth lambda was detected. The pressure independent ratio 2 Delta(0)/k(B)T(c)=3.72(2) (Delta(0) is the superconducting gap at zero temperature) was found to be close to the BCS value 3.52. Magnetization and muon-spin rotation measurements of lambda(T) indicate that RbOs2O6 is an adiabatic s-wave BCS-type superconductor. The value of lambda extrapolated to zero temperature and ambient pressure was estimated to be 230(30) nm.

Muon-spin-rotation measurements of the penetration depth in Li 2 Pd 3 B

Measurements of the magnetic field penetration depth

Comparison of different methods for analyzing μSR line shapes in the vortex state of type-II superconductors

\lambda

Magnetic penetration depth inRbOs2O6studied by muon spin rotation

in the ternary boride superconductor Li

Nonlinear pressure dependence of TN in almost multiferroic EuTiO3

_2

Superfluid density and superconducting gaps of RbFe 2 As 2 as a function of hydrostatic pressure

Pd

Muon-spin rotation measurements of the magnetic penetration depth in the iron-based superconductor Ba 1 − x Rb x Fe 2 As 2

_3

μSR investigation of magnetism and magnetoelectric coupling in Cu2OSeO3

B (