Structure-property relationship of CoMnSi thin films in response to He-irradiation.

We investigated the structure-property relationship of CoMnSi Heusler thin films upon the irradiation with He ions. The variation of the crystal structure with increasing ion fluence has been probed using nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM), and associated with the corresponding changes of the magnetic behavior. A decrease of both the structural order and the moment in saturation is observed.

Effects of Quantum Spin-1/2 Impurities on the Magnetic Properties of Zigzag Spin Chains.

We investigate the effect of Co^{2+} (spin-1/2) impurities on the magnetic ground state and low-lying spin excitations of the quasione-dimensional spin-1/2 antiferromagnet SrCuO_{2} by means of neutron scattering, muon spin spectroscopy, and bulk (ac and dc) magnetic susceptibilities. We found that dilute Co doping induces an Ising-like anisotropy and enhances the magnetic ordering temperature rather significantly, but preserves the gapless nature of the spin excitations. These results are in apparent contradiction with the recent studies of Ni (spin-1) doped SrCuO_{2}.

Superconductivity in Sm-doped [n]phenacenes (n = 3, 4, 5).

We report here the discovery of a new aromatic hydrocarbon superconductor, Sm-doped chrysene, with Tc ∼ 5 K, and compare its behavior with those measured in the full series of Sm-doped [n]phenacene superconductors, with n = 3, 4, 5, thus determining the trend of Tc as a function of the number of fused benzene rings and for an odd or even number of units.

Spin gap in the zigzag spin-1/2 chain cuprate Sr(0.9)Ca(0.1)CuO(2).

We report a comparative study of (63)Cu nuclear magnetic resonance spin lattice relaxation rates T(1)(-1) on undoped SrCuO(2) and Ca-doped Sr(0.9)Ca(0.1)CuO(2) spin chain compounds.

Nanoscale electronic order in iron pnictides.

The charge distribution in RFeAsO1-xFx (R=La,Sm) iron pnictides is probed using As nuclear quadrupole resonance. Whereas undoped and optimally doped or overdoped compounds feature a single charge environment, two charge environments are detected in the underdoped region. Spin-lattice relaxation measurements show their coexistence at the nanoscale.