A method of fabricating high aspect ratio ceramic structures in which a selected portion of perovskite or perovskite-like crystalline material is exposed to a high energy ion beam for a time sufficient to cause the crystalline material contacted by the ion beam to have substantially parallel columnar defects. Then selected portions of the material having substantially parallel columnar defects are etched leaving material with and without substantially parallel columnar defects in a predetermined shape having high aspect ratios of not less than 2 to 1. Etching is accomplished by optical or PMMA lithography. There is also disclosed a structure of a ceramic which is superconducting at a temperature in the range of from about 10° K. to about 90° K. with substantially parallel columnar defects in which the smallest lateral dimension of the structure is less than about 5 microns, and the thickness of the structure is greater than 2 times the smallest lateral dimension of the structure.