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arXiv · 1006.5257

Nonmagnetic impurity perturbation to the quasi-two-dimensional quantum helimagnet LiCu2O2

H. C. Hsu·J. -Y. Lin·W. L. Lee·M. -W. Chu·T. Imai·Y. J. Kao·C. D. Hu·H. L. Liu·F. C. Chou
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Abstract

A complete phase diagram of Zn substituted quantum quasi-two-dimensional helimagnet LiCu2O2 has been presented. Helical ordering transition temperature (T_h) of the original LiCu2O2 follows finite size scaling for less than ~ 5.5% Zn substitution, which implies the existence of finite helimagnetic domains with domain boundaries formed with nearly isolated spins. Higher Zn substitution > 5.5% quenches the long-range helical ordering and introduces an intriguing Zn level dependent magnetic phase transition with slight thermal hysteresis and a universal quadratic field dependence for T_c (Zn > 0.055,H). The magnetic coupling constants of nearest-neighbor (nn) J1 and next-nearest-neighbor (nnn) J2 (alpha=J2/J1) are extracted from high temperature series expansion (HTSE) fitting and N=16 finite chain exact diagonalization simulation. We have also provided evidence of direct correlation between long-range helical spin ordering and the magnitude of electric polarization in this spin driven multiferroic material.

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H. C. Hsu, J. -Y. Lin, W. L. Lee, M. -W. Chu, T. Imai, Y. J. Kao, C. D. Hu, H. L. Liu, F. C. Chou. 2010-06-28. Nonmagnetic impurity perturbation to the quasi-two-dimensional quantum helimagnet LiCu2O2. https://doi.org/10.1103/physrevb.82.094450

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