Surface induced chemical disorder and step unpairing transition are investigated by grazing x-ray diffraction on a vicinal surface of an $A_{3}B$ type alloy $\left({\mathrm{Cu}}_{83}{\mathrm{Pd}}_{17}\right)$. Both transformations occur below and close to the bulk order-disorder transition. The asymmetry of terraces and the order parameter reflecting chemical order in the surface layer are determined by measuring the shape of crystal truncation rods. Step unpairing and surface disordering are found to be continuous transitions.

Close

PrevNext

View figure in article