Depth-dependent critical behavior inV2H

Abstract

Using x-ray diffuse scattering, we investigate the critical behavior of an order-disorder phase transition in a defective ``skin layer'' of ${\text{V}}_{2}\text{H}$. In the skin layer, there exist walls of dislocation lines oriented normal to the surface. The density of dislocation lines within a wall decreases continuously with depth. We find that, because of this inhomogeneous distribution of defects, the transition effectively occurs at a depth-dependent local critical temperature. A depth-dependent scaling law is proposed to describe the corresponding critical ordering behavior.