  Electric-field controlled magnetization dynamics is an important integrant in
low power spintronic devices. In this letter, we demonstrate electric-field
induced parametric excitation for CoFeB/MgO junctions by using interfacial
in-plane magnetic anisotropy. When the in-plane magnetic anisotropy and the
external magnetic field are parallel to each other, magnons are efficiently
excited by using electric-field induced parametric excitation. Its wavelength
and wavenumber are tuned by changing input power and frequency of the applied
voltage. A generalized phenomenological model is developed to explain the
underlying role of the electric-field torque. Electrical excitation with no
Joule heating offers a good opportunity for developing magnonic devices and
exploring various nonlinear dynamics in magnetic systems.
