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Comment on “Strong dependence of the interlayer coupling on the hole mobility in antiferromagnetic La_ {2− x} Sr_ {x} CuO_ {4}(x< 0.02)”

Physical review. B, Condensed matter (Impact Factor: 3.77). 11/2005; 73(10). DOI: 10.1103/PhysRevB.73.106501
Source: arXiv

ABSTRACT Using the experimental data given in the above paper, we show that—unlike the effective coupling discussed in this paper—the net average antiferromagnetic interlayer coupling in doped lanthanum cuprates depends only weakly on the doping or on the temperature. We argue that the effective coupling is proportional to the square of the staggered magnetization, and does not supply new information about the origin of the suppression of the magnetic order in doped samples. Our analysis is based on a modified version of the equation describing the spin-flip transition, which takes into account the decrease of the staggered moment with temperature and doping.

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    ABSTRACT: We study the order-from-disorder transition and reentrant magnetism in La2−xSrxCu1−zZnzO4 within the framework of a long-wavelength nonlinear sigma model that properly incorporates the Dzyaloshinskii-Moriya and XY anisotropies. Doping with nonmagnetic impurities, such as Zn, is considered according to classical percolation theory, whereas the effect of Sr, which introduces charge carriers into the CuO2 planes, is described as a dipolar frustration of the antiferromagnetic order. We calculate several magnetic, thermodynamic, and spectral properties of the system, such as the antiferromagnetic order parameter, σ0, the Néel temperature, TN, the spin-stiffness, ρs, and the anisotropy gaps, ΔDM and ΔXY, as well as their evolution with both Zn and Sr doping. We explain the nonmonotonic and reentrant behavior experimentally observed for TN(x,z) by Hücker et al. Phys. Rev. B 59 R725 (1999)], as resulting from the reduction, due to the nonmagnetic impurities, of the dipolar frustration induced by the charge carriers (order-from-disorder). Furthermore, we find a similar nonmonotonic and reentrant behavior for all the other observables studied. Most remarkably, our results show that while for x≈2% and z=0 the Dzyaloshinskii-Moriya gap ΔDM=0, for z=15% it is approximately ΔDM≈7.5 cm−1, and we expect it could be observed with one-magnon Raman spectroscopy.
    Physical review. B, Condensed matter 10/2006; 75(13). · 3.77 Impact Factor

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