  We describe a reversible, spatially-controlled doping method for cuprate
films. The technique has been used to create superconductor-antiferromagnetic
insulator-superconductor (S-AFI-S) junctions and optimally doped
superconductor-underdoped superconductor-optimally doped superconductor
(OS-US-OS) cuprate structures. We demonstrate how the S-AFI-S structure can be
employed to reliably measure the transport properties of the antiferromagnetic
insulator region at cryogenic temperatures using the superconductors as
seamless electrical leads. We also discuss applied and fundamental issues which
may be addressed with the structures created with this doping method. Although
it is implemented on a cuprate film (YBa2Cu3O7-delta) in this work, the method
can also be applied to any mixed-valence transition metal oxide whose physical
properties are determined by oxygen content.

Superconductivity;Strongly Correlated Electrons