Why is SrTiO3 much stronger at nanometer than at centimeter scale?

Nanoindentation of (100), (110) and (111) oriented SrTiO3 single crystals at room temperature led to the appearance of slip bands and simultaneously to discontinuities in the force-penetration curve. Combining both enabled a critical shear stress of the order of 10 GPa to be evaluated which indicates the onset of dislocation generation. Transmission electron microscopy proved that dislocations were nucleated underneath the indenter. The difference between macroscopically and nanoscopically stressed volumes arises due to the availability of mobile dislocations in the former case and due a lack of such dislocations in the latter.

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