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Freezing of anisotropic spin clusters in La1.98Sr0.02CuO4

M. Matsuda·Y. S. Lee·M. Greven·M. A. Kastner·R. J. Birgeneau·K. Yamada·Y. Endoh·P. Boeni·S. -H. Lee·S. Wakimoto·G. Shirane
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Abstract

A spin-glass compound, La$_{1.98}$Sr$_{0.02}$CuO$_4$, shows quasi-three-dimensional magnetic ordering below $\sim$40 K. A remarkable feature is that the magnetic correlation length along the orthorhombic $a\rm_{ortho}$ axis is much longer than that along the $b\rm_{ortho}$ axis, suggesting that the spin structure is closely related to the diagonal stripe structure. The spin-glass state can be expressed as a random freezing of quasi-three-dimensional spin clusters with anisotropic spin correlations ($ξ'_a\sim160$ Å, $ξ'_b\sim25$ Å, and $ξ'_c\sim4.7$ Åat 1.6 K). The new magnetic state is important as an intermediate phase between the three-dimensional antiferromagnetic ordered phase in La$_2$CuO$_4$ and the incommensurate phase in La$_{1.95}$Sr$_{0.05}$CuO$_4$ in which the positions of the incommensurate peaks are rotated by 45$^\circ$ in reciprocal space about ($π$,$π$) from those observed in the superconducting La$_2$CuO$_4$ compounds.

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M. Matsuda, Y. S. Lee, M. Greven, M. A. Kastner, R. J. Birgeneau, K. Yamada, Y. Endoh, P. Boeni, S. -H. Lee, S. Wakimoto, G. Shirane. 1999-11-06. Freezing of anisotropic spin clusters in La1.98Sr0.02CuO4. https://doi.org/10.1103/physrevb.61.4326

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