  We have investigated the magnetoelectric (ME) effect in layered composite
rings subjected to circumferential AC magnetic fields and DC magnetic fields in
radial, axial or circumferential directions. Bilayer samples were obtained
combining different grades of commercial Mn-Zn ferrites or Ni-Zn ferrites with
commercial lead zirconate titanate (PZT). Mn-Zn ferrites with low
magnetostriction saturation () and low magneto-crystalline anisotropy constants
show high ME capabilities when associated with PZT in ring structures. In
certain conditions, these ME effects are higher than those obtained with
Terfenol-D/PZT composites in the same layered ring structure. Magnetostrictive
and mechanical characterizations have given results that explain these high ME
performances. Nevertheless, Mn-Zn ferrite/PZT composites exhibit voltages
responses with low linearity especially at high signal level. Based on the
particular structure of the ME device, a method to decrease the nonlinear
harmonic distortion of the ME voltages is proposed. Harmonic distortion
analysis of ME voltages measured in different configurations allows us to
explain the phenomenon.
