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arXiv · 1201.6663

Ca2Y2Cu5O10: the first frustrated quasi-1D ferromagnet close to criticality

R. O. Kuzian·S. Nishimoto·S. -L. Drechsler·J. Malek·S. Johnston·J. van den Brink·M. Schmitt·H. Rosner·M. Matsuda·K. Oka·H. Yamaguchi·T. Ito
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Abstract

Ca2Y2Cu5O10 is build up from edge-shared CuO4 plaquettes forming spin chains. From inelastic neutron scattering data we extract an in-chain nearest neighbor exchange J1 approximately -170 K and the frustrating next neighbor J2 approximately 32 K interactions, both significantly larger than previous estimates. The ratio alpha= J2/J1 approximately 0.19 places the system very close to the critical point alpha_c=0.25 of the J1-J2 chain, but in the ferromagnetic regime. We establish that the vicinity to criticality only marginally affects the dispersion and coherence of the elementary spin-wave-like magnetic excitations, but instead results in a dramatic T-dependence of high-energy Zhang-Rice singlet excitation intensities.

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R. O. Kuzian, S. Nishimoto, S. -L. Drechsler, J. Malek, S. Johnston, J. van den Brink, M. Schmitt, H. Rosner, M. Matsuda, K. Oka, H. Yamaguchi, T. Ito. 2012-02-09. Ca2Y2Cu5O10: the first frustrated quasi-1D ferromagnet close to criticality. https://doi.org/10.1103/physrevlett.109.117207

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