Abstract
The high-resolution Bitter pattern technique has been used to reveal the magnetic structure of single-crystal samples of high-Tc superconductor YBa2Cu3O7 at 4.2 K. Typical patterns consist of hexagonally correlated, singly quantized vortices of flux hc2e. That is, the structures are comparable to those that would be observed in conventional type-II superconductors under similar conditions. © 1987 The American Physical Society.