Fabrication and Characterization of YBa$_{2}$Cu$_{3}$O$_{7}$ and La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ Nanostructures*

We present a novel technique to fabricate nanostructures of superconducting YBa$_{2}$Cu$_{3}$O$_{7}$ and ferromagnetic La$_{0.67}$Ca$_{0.33}$MnO$_{3}$. The nanostructures are in the form of Aharonov-Bohm rings and ultralong wires with very high aspect ratios, intended to study quantum interference phenomena at mesoscopic length scales in these materials. The fabrication involves deep nano-patterning of SrTiO$_{3}$ substrates using focused ion beam (FIB) and epitaxial thin-film growth using pulsed laser-ablated deposition (PLD). The samples are characterized by electrical transport measurements under cryomagnetic conditions, and various high-resolution microscopies including AFM, SEM, TEM, and STM. Our fabrication technique combining FIB and PLD provides a reliable general method for nano-structuring complex oxide materials.