### Abstract

The results of high-resolution synchrotron x-ray-scattering experiments on the normal-incommensurate phase transition in Rb2ZnCl4 are reported. Measured critical exponents for the intensities of the first three harmonics of the incommensurate modulation wave below T-c agree well with theoretical predictions for the n=2, D=3 (SD-XY) universality class. The scattering observed above T-c corrresponds to critical fluctuations on two distinct length scales: the critical exponents for the short length scale component of the scattering agree with those expected for the 3D-XY universality class. The value found for the exponent of the inverse correlation length of the long length scale component is nu(s)=0.7+/-0.2. A comparison of data taken in Laue and Bragg geometries at different photon energies suggests that the second length scale scattering originates in the near-surface region. Possible explanations of the two length scale behavior are discussed.

Original language | English |
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Journal | Physical Review B |

Volume | 54 |

Issue number | 5 |

Pages (from-to) | 3115-3124 |

ISSN | 2469-9950 |

DOIs | |

Publication status | Published - 1996 |

## Cite this

Zinkin, M. P., McMorrow, D. F., Hill, J. P., Cowley, R. A., Lussier, J. G., Gibaud, A., Grübel, G., & Sutter, C. (1996). Synchrotron x-ray-scattering study of the normal-incommensurate phase transition in Rb

_{2}ZnCl_{4}.*Physical Review B*,*54*(5), 3115-3124. https://doi.org/10.1103/PhysRevB.54.3115