  We realize a nanoscale-area Mach-Zehnder interferometer with co-propagating
quantum Hall spin-resolved edge states and demonstrate the persistence of
gate-controlled quantum interference oscillations, as a function of an applied
magnetic field, at relatively large temperatures. Arrays of top-gate magnetic
nanofingers are used to induce a resonant charge transfer between the pair of
spin-resolved edge states. To account for the pattern of oscillations measured
as a function of magnetic field and gate voltage, we have developed a simple
theoretical model which satisfactorily reproduces the data.
