Near-Surface Long-Range Order at the Ordinary Transition

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 ( ε expansion), we find that for T≥Tcᵇ 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^κ (with κ≡1-η_⊥ᵒʳᵈ0.21 for the d0ex0ex=0ex0ex3 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.