Publications (8)15.74 Total impact

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ABSTRACT: The effect of pressure on the copper and praseodymium magnetic order in the system Nd(1x)$Pr(x)Ba2Cu3$O7 with x=0.3, 0.5, 0.7, and 1 was investigated by means of the muon spin rotation (muSR) technique. It was found that the effect of pressure on the Neel temperatures of both copper and praseodymium is positive for the whole range of Pr concentrations (0.3<x<1) studied. These findings are in contrast with a number of previous reports and clarify some of the puzzles related to the effect of pressure on superconductivity and magnetism in the praseodymiumsubstituted R}(1x)$Pr(x)Ba2Cu3O7 systems, where R is a rare earth element.  [Show abstract] [Hide abstract]
ABSTRACT: A detailed zero and transversefield muon spin rotation investigation of magnetism and the magnetoelectric coupling in Cu2OSeO3 is reported. An internal magnetic field Bint(T=0)=85.37(25) mT was found, in agreement with a ferrimagnetic state below Tc=57.0(1) K. The temperature dependence of the magnetic order parameter is well described by the relation Bint=B(0)(1−(T/Tc)2)β̃ with an effective exponent β̃≃0.39(1), which is close to the critical exponent β≃1/3 for a threedimensional (3D) magnetic system. Just above Tc the muon relaxation rate follows the power law λ(T)∝(T/Tc−1)−ω̃ with ω̃=1.06(9), which is characteristic for 3D ferromagnets. Measurements of Bint(T) with and without an applied electrostatic field E=1.66×105 V/m suggest a possible electricfield effect of magnitude ΔBV=BV(0 V)−BV(500 V)=−0.4(4) mT. ©2011 American Physical Society  [Show abstract] [Hide abstract]
ABSTRACT: Zeeman perturbed nuclear quadrupole resonance was applied to evaluate weak magnetic fields in the context of orbital currents in cuprate superconductors. The magnetic environment of the barium atom in caxis oriented powder samples of YBa2Cu4O8 was investigated in the pseudogap phase at 90 K. No evidence for orbital currents was found: Any static and dynamic field must be less than 0.07mT and 0.7mT respectively. 
Article: MuonSpin Rotation Study of the Ternary Noncentrosymmetric Superconductors Li 2 Pd x Pt 3− x B
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ABSTRACT: We investigated the superconducting state of the noncentrosymmetric superconductors Li2Pd x Pt3−x B with superconducting transition temperature T c=5.16(8) K (x=2.25), 3.56(8) K (x=1.5) and 2.60 K (x=0) by means of muonspin rotation (μSR) and specific heat experiments. The μSR relaxation rate σ sc was found to be constant at low temperatures for all the compounds. Data taken at different magnetic fields show that the magnetic penetration depth λ is fieldindependent for Li2Pd2.25Pt0.75B and Li2Pt3B. The electronic contribution to the specific heat measured in Li2Pd1.5Pt1.5B and Li2Pt3B increases exponentially at the lowest temperatures. These features suggest that the whole family of Li2Pd x Pt3−x B comprises singlegap swave superconductors across the entire doping regime.  [Show abstract] [Hide abstract]
ABSTRACT: We investigated the superconducting state of the noncentrosymmetric superconductors Li2Pd x Pt3−x B with superconducting transition temperature T c=5.16(8) K (x=2.25), 3.56(8) K (x=1.5) and 2.60 K (x=0) by means of muonspin rotation (μSR) and specific heat experiments. The μSR relaxation rate σ sc was found to be constant at low temperatures for all the compounds. Data taken at different magnetic fields show that the magnetic penetration depth λ is fieldindependent for Li2Pd2.25Pt0.75B and Li2Pt3B. The electronic contribution to the specific heat measured in Li2Pd1.5Pt1.5B and Li2Pt3B increases exponentially at the lowest temperatures. These features suggest that the whole family of Li2Pd x Pt3−x B comprises singlegap swave superconductors across the entire doping regime. 
Technical Report: Superconductivity and magnetism
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ABSTRACT: During the reporting period we continued our research activities in the field of novel electronic materials. We investigated their magnetic and electronic properties by combining experiments using microscopic tools, such as muonspin rotation (µSR), electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), nuclear quadrupole resonance (NQR), and the more macroscopic techniques of SQUID and torque magnetometry.From our various investigations we present in the following three studies which are currently of highest interest in this research field. 
Article: Muon spin rotation study of the ternary noncentrosymmetric superconductors Li$_2$Pd$_x$Pt$_{3x}$B
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ABSTRACT: We investigated the superconducting state of the noncentrosymmetric superconductors Li$_2$Pd$_x$Pt$_{3x}$B with superconducting transition temperature $T_c$= 5.16(8) K ($x$=2.25), 3.56(8) K ($x=1.5$) and 2.60 K ($x=0$) by means of muonspin rotation ($\mu$SR) and specific heat experiments. The $\mu$SR relaxation rate $\sigma_{sc}$ was found to be constant at low temperatures for all the compounds. Data taken at different magnetic fields show that the magnetic penetration depth $\lambda$ is fieldindependent for Li$_2$Pd$_{2.25}$Pt$_{0.75}$B and Li$_2$Pt$_{3}$B. The electronic contribution to the specific heat measured in Li$_2$Pd$_{1.5}$Pt$_{1.5}$B and Li$_2$Pt$_{3}$B increases exponentially at the lowest temperatures. These features suggest that the {\it whole family} of Li$_2$Pd$_x$Pt$_{3x}$B are singlegap swave superconductors across the entire doping regime.
Publication Stats
65  Citations  
15.74  Total Impact Points  
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Institutions

20092012

University of Zurich
 Institute for Geophysics
Zürich, Zurich, Switzerland
