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Phys. Rev. Lett. 77, 3645–3648 (1996)

[Issue 17 – October 1996 ]

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Near-Surface Long-Range Order at the Ordinary Transition

Uwe Ritschel and Peter Czerner

Fachbereich Physik, Universität GH Essen, 45117 Essen, FR Germany

We study the spatial dependence of the order parameter m(z) near surface that reduces the tendency to order. Using scaling arguments and perturbative methods ( epsilon expansion), we find that for T >= T^b_c a small surface magnetic field h₁ gives rise to a macroscopic length scale and an anomalous short-distance increase of m(z), governed by the power law m~z ^kappa (with kappa =1- eta ^ord_perp~=0.21 for the d = 3 Ising model). This result is related to experiments where exponents of the ordinary transition were observed in Fe₃Al, while superstructure reflections revealed the existence of long-range order near the surface.

©1996 The American Physical Society

URL: http://publish.aps.org/abstract/PRL/v77/p3645
PACS: 75.40.Cx, 68.35.Rh, 75.30.Pd, 78.70.Ck

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References

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