  Strain and defects in crystalline materials are responsible for the distinct
mechanical, electric and magnetic properties of a desired material, making
their study an essential task in material characterization, fabrication and
design. Existing techniques for the visualization of strain fields, such as
transmission electron microscopy and diffraction, are destructive and limited
to thin slices of the materials. On the other hand, non-destructive X-ray
imaging methods either have a reduced resolution or are not robust enough for a
broad range of applications. Here we present X-ray ptychographic topography, a
new method for strain imaging, and demonstrate its use on an InSb micro-pillar
after micro-compression, where the strained region is visualized with a spatial
resolution of 30 nm. Thereby, X-ray ptychographic topography proves itself as a
robust non-destructive approach for the imaging of strain fields within bulk
crystalline specimens with a spatial resolution of a few tens of nanometers.
