Sirko Kamusella

Coexistence of 3d‐Ferromagnetism and Superconductivity in [(Li1−xFex)OH](Fe1−yLiy)Se

Superconducting [(Li1-x Fex )OH](Fe1-y Liy )Se (x≈0.2, y≈0.08) was synthesized by hydrothermal methods and characterized by single-crystal and powder X-ray diffraction. The structure contains alternating layers of anti-PbO type (Fe1-y Liy )Se and (Li1-x Fex )OH. Electrical resistivity and magnetic susceptibility measurements reveal superconductivity at 43 K. An anomaly in the diamagnetic shielding indicates ferromagnetic ordering near 10 K while superconductivity is retained. The ferromagnetism is from the iron atoms in the (Li1-x Fex )OH layer. Isothermal magnetization measurements confirm the superposition of ferromagnetic and superconducting hysteresis. The internal ferromagnetic field is larger than the lower, but smaller than the upper critical field of the superconductor. The formation of a spontaneous vortex phase where both orders coexist is supported by (57) Fe-Mössbauer spectra, (7) Li-NMR spectra, and μSR experiments.

Coexistence of low-moment magnetism and superconductivity in tetragonal FeS and suppression of T-c under pressure

We report local probe (mu SR) measurements on the recently discovered tetragonal FeS superconductor which has been predicted to be electronically very similar to superconducting FeSe. Most remarkably, we find that low-moment (10(-2)-10(-3) mu B) disordered magnetism with a transition temperature of T-N approximate to 20 K microscopically coexists with bulk superconductivity below T-c = 4.3(1) K. From transverse field mu SR we obtain an in-plane penetration depth lambda(ab)(0) = 223(2) nm for FeS. The temperature dependence of the corresponding superfluid density lambda(-2)(ab)(T) indicates a fully gapped superconducting state and is consistent with a two gap s-wave model. Additionally, we find that the superconducting T-c of FeS continuously decreases for hydrostatic pressures up to 2.2 GPa.

Diluted paramagnetic impurities in nonmagnetic Ba2YIrO6

The cubic double perovskite Ba

Interplay of magnetism and superconductivity in EuFe2(As1-xPx)2 single crystals probed by muon spin rotation and 57Fe Mössbauer spectroscopy

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Magnetic order and spin dynamics inLa2O2Fe2OSe2probed byFe57Mössbauer,La139NMR, and muon-spin relaxation spectroscopy

YIrO

Hydrothermal synthesis and structure determination of a new calcium iron ruthenium hydrogarnet

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CDW order and unconventional s-wave superconductivity in Ba1-xNaxTi2Sb2O

has been investigated by the local probe techniques nuclear magnetic resonance (

Moessfit: A free Mössbauer fitting program

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Coexistence of superconductivity and magnetism inCa1−xNaxFe2As2: Universal suppression of the magnetic order parameter in 122 iron pnictides

Y NMR) and muon spin rotation (muSR). Both methods confirm the absence of magnetic long-range order in this compound but find evidence for diluted localized paramagnetic moments. NMR spin-lattice relaxation rate 1/T1 measurements suggest a slowing down of localized spin moments at low temperatures. An increase of the muSR spin-lattice relaxation rate lambda confirms the presence of weak magnetism in Ba

1/3 magnetization plateau and frustrated ferrimagnetism in a sodium iron phosphite

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