Browsing by Author "Rosner, H"

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    Magnetic properties and exchange integrals of the frustrated chain cuprate linarite PbCuSO4(OH)2
    (American Physical Society, 2012-01-05) Wolter, AUB; Lipps, F; Schäpers, M; Drechsler, SL; Nishimoto, S; Vogel, R; Kataev, V; Büchner, B; Rosner, H; Schmitt, M; Uhlarz, M; Skourski, Y; Wosnitza, J; Süllow, S; Rule, KC
    We present a detailed study in the paramagnetic regime of the frustrated s = 1/2 spin-compound linarite PbCuSO4(OH)(2) with competing ferromagnetic nearest-neighbor and antiferromagnetic next-nearest-neighbor exchange interactions. Our data reveal highly anisotropic values for the saturation field along the crystallographic main directions, with similar to 7.6, similar to 10.5, and similar to 8.5 T for the a, b, and c axes, respectively. In the paramagnetic regime, this behavior is explained mainly by the anisotropy of the g factor, but leaving room for an easy-axis exchange anisotropy. Within the isotropic J(1)-J(2) spin model, our experimental data are described by various theoretical approaches, yielding values for the exchange interactions J(1) similar to -100 K and J(2) similar to 36 K. These main intrachain exchange integrals are significantly larger as compared to the values derived in two previous studies in the literature and shift the frustration ratio alpha = J(2)/vertical bar J(1)vertical bar approximate to 0.36 of linarite closer to the one-dimensional critical point at 0.25. Electron spin resonance (ESR) and nuclear magnetic resonance (NMR) measurements further prove that the static susceptibility is dominated by the intrinsic spin susceptibility. The Knight shift as well as the broadening of the linewidth in ESR and NMR at elevated temperatures indicate a highly frustrated system with the onset of magnetic correlations far above the magnetic ordering temperature T-N = 2.75(5) K, in agreement with the calculated exchange constants. © 2012, American Physical Society.
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    Superconductivity and magnetism in R4Be33Pt16 (R=Y, La–Nd, Sm–Lu ): a family of crystallographically complex noncentrosymmetric compounds
    (American Physical Society, 2021-07-14) Svanidze, E; Amon, A; Nicklas, M; Prots, Y; Juckel, M; Rosner, H; Burkhardt, U; Avdeev, M; Grin, Y; Leithe-Jasper, A
    Crystallographically complex compounds often possess peculiar physical properties, the evolution of which can be tracked by changing one of the constituent elements at a time. We report the discovery and synthesis of isotypic R4Be33Pt16 (R = Y, La–Nd, Sm–Lu) compounds, which crystallize with the noncentrosymmetric cubic pace group I¯43d. The lattice parameters vary from a=13.6682(4)Å for R = La to a=13.4366(3)Å for R = Lu. R4Be33Pt16 phases exhibit a wide range of ground states. R = Y, La, and Lu analogs display uperconductivity. their calculated electronic structures show nonzero density of states at the Fermi level, with the value of the Sommerfeld coefficient consistent with those obtained experimentally. The rest of the R4Be33Pt16 compounds exhibit magnetic ground states with ordering temperatures ranging from Tmag=0.4 K (R = Yb) to Tmag=40 K R r). The diversity of physical properties of R4Be33Pt16 compounds can likely be attributed to the nature of the ndividual rare-earth elements, structural noncentrosymmetry, the large number of atoms per unit cell (212), as well as the complex multicenter interactions within the Be-Pt framework. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license