Nonlinear electric field tuning characteristics of yttrium iron garnet–lead zirconate titanate microwave resonators

This report is on hysteresis and switching associated with electric field (E) tuning of ferromagnetic resonance in a bilayer of yttrium iron garnet (YIG)-lead zirconate titanate (PZT). The tuning is facilitated by piezoelectricity of PZT and mechanical bonding with YIG. For E<2kV∕cm, the frequency shift δf is linear with E. For E<10kV∕cm a pronounced hysteresis is seen in δf versus E. For E>10kV∕cm, a butterflylike dependence of δf with an abrupt switch in the sign and magnitude of δf are measured. The observations are attributed to nonlinearities of the piezoelectric deformation.