Order-disorder transitions between glassy phases are common in nature and yet a comprehensive survey on the entailed structural changes is challenging since the constituents are in the micro-scale. Vortex matter in type-II superconductors is a model system where some of these experimental challenges can be tackled. Samples with point disorder present a glassy transition on increasing the density of vortices. A glassy yet quasi-crystalline phase, the Bragg glass, nucleates at low densities. The vortex glass stable at high densities is expected to be disordered, however its detailed structural properties remained experimentally elusive. Here we show that the vortex glass has large crystallites with in-plane positional displacements growing algebraically and short-range orientational order. Furthermore, the vortex glass has a finite and almost constant correlation length along the direction of vortices, in sharp contrast with strong entanglement. These results are important for the understanding of disorder-driven phase transitions in glassy condensed matter.

玻璃相之间的有序-无序过渡在自然界中是很普遍的，但是由于组成部分是微尺度的，因此对所涉及的结构变化进行全面的调查是具有挑战性的。II型超导体中的涡旋物质是一个模型系统，可以解决其中的一些实验难题。点紊乱的样品在增加涡旋密度时呈现玻璃态转变。布拉格玻璃是一种玻璃状但准结晶的相，它以低密度成核。预计在高密度下稳定的涡流玻璃会无序，但是其详细的结构特性在实验上仍然难以捉摸。在这里，我们显示出旋涡玻璃具有大的微晶，其平面内位移随代数和短程方向有序增长。此外，涡旋玻璃沿涡旋方向具有有限且几乎恒定的相关长度，与强纠缠形成鲜明对比。这些结果对于理解玻璃态凝结物中无序驱动的相变非常重要。