Electrically tunable ferrite-ferroelectric microwave delay lines

The electric field control of delay time is observed in a ferrite-ferroelectric microwave delay line. A microstrip delay line with a bilayer of (111) yttrium iron garnet film and (001) lead magnesium niobate-lead titanate (PMN-PT) is studied. A 10-25% variation in delay time is measured when the electric field applied to the PMN-PT layer is increased from 0 to 8 kV/cm. The tunability is attributed to variations in the permittivity for PMN-PT in an electric field and its effect on the dispersion characteristics of hybrid spin electromagnetic waves that are excited in the bilayer. (c) 2005 American Institute of Physics.