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MA: Magnetismus
MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)
MA 14.139: Poster
Tuesday, March 25, 2003, 15:15–19:15, Zelt
13C–NMR on the S = 1/2 afm coupled spin chain compound [PM·Cu(NO3)2·(H2O)2]n (PM = pyrimidine) — •A.U.B. Wolter1,2, S. Süllow1, H.-H. Klauß1, F.J. Litterst1, P. Wzietek2, D. Jérome2, and R. Feyerherm3 — 1IMNF, TU Braunschweig, 38106 Braunschweig, Germany — 2LPS, Université Paris-Sud, 91405 Orsay, France — 3HMI, 14109 Berlin, Germany
We present NMR experiments on the antiferromagnetically coupled 1D Heisenberg spin-chain (PMCu(NO3)2(H2O)2)n, PM = Pyrimidin = C4H4N2 with a magnetic exchange J/kB = 36 K [1]. In this system with an alternating Cu environment the spin orbit interaction gives rise to an effective staggered field h perpendicular to an externally applied field H [1,2]. It causes a staggered magnetization component m ⊥ H and an anisotropic field–induced gap in the spin excitation spectrum. From NMR-shift investigations as function of temperature and field orientation, we determine the staggered magnetization m. We will discuss our results on basis of the models developed by Oshikawa and Affleck [2].
[1] R. Feyerherm et al., J. Phys.: Condens. Matter 12 (2000) 8495
[2] M. Oshikawa and I. Affleck, Phys. Rev. Lett.79 (1997) 2883