14 research outputs found
Low frequency and Microwave Magnetoelectric Effects in Thick Film Heterostructures of Lithium Zinc Ferrite and Lead Zirconate Titanate
Magnetoelectric (ME) coupling at low frequencies and at x-band have been
investigated in layered samples containing zinc substituted lithium ferrite and
lead zirconate titanate (PZT). Multilayers of Li0.5-x/2ZnxFe2.5-x/2O4 (LZFO)
(x=0-0.4) and PZT were prepared by lamination and sintering of thick films. At
low frequencies (10-1000 Hz), the ME voltage coefficient for transverse fields
is higher than for longitudinal fields. With Zn substitution in the ferrite,
transverse coupling increases to a maximum for x=0.3 and then decreases for
higher x. Analysis based on our model for a bilayer implies an efficient
magneto-mechanical coupling with Zn substitution, resulting in strong ME
interactions. Microwave ME coupling is studied through measurements of shift in
the ferromagnetic resonance field due to an applied electric field. Estimated
ME constants from such data are in agreement with our model for a ferrite-PZT
bilayer.Comment: To be published in Solid State Communication
Frequency Dependence of Magnetoelectric Interactions in Layered Structures of Ferromagnetic Alloys and Piezoelectric Oxides
Magnetoelectric (ME) interactions in layered structures of magnetostrictive
and piezoelectric phases are mediated by mechanical deformation. Here we
discuss the frequency dependence of ME coupling in bilayers and trilayers of
Permendur, a ferromagnetic alloy, and lead zirconate titanate. Data on ME
voltage coefficient versus frequency profiles reveal a giant ME coupling at
electromechanical resonance. The maximum voltage coefficient of 90 V/cm Oe is
three orders of magnitude higher than low-frequency values. The ME interactions
for transverse fields is an order of magnitude stronger than for longitudinal
fields. These results are in agreement with theory. The resonance ME effect,
therefore, is a novel tool for enhancing the magnetic-to-electric field
conversion efficiency in the composites.Comment: accepted for publication as rapid communication in Applied Physics
Resonance magnetoelectric effects in layered magnetostrictive-piezoelectric composites
Magnetoelectric interactions in bilayers of magnetostrictive and
piezoelectric phases are mediated by mechanical deformation. Here we discuss
the theory and companion data for magnetoelectric (ME) coupling at
electromechanical resonance (EMR) in a ferrite-lead zirconate titanate (PZT)
bilayer. Estimated ME voltage coefficient versus frequency profiles for nickel,
cobalt, or lithium ferrite and PZT reveal a giant ME effect at EMR with the
highest coupling expected for cobalt ferrite-PZT. Measurements of resonance ME
coupling have been carried out on layered and bulk composites of nickel
ferrite-PZT. We observe a factor of 40-600 increase in ME voltage coefficient
at EMR compared to low frequency values. Theoretical ME voltage coefficients
versus frequency profiles are in excellent agreement with data. The resonance
ME effect is therefore a novel tool for enhancing the field conversion
efficiency in the composites
Direct and converse magnetoelectric effect at resonant frequency in laminar piezoelectric-magnetostrictive composite.
Laminar piezoelectric-magnetostrictive composites using piezoelectric lead
zirconate titanate ceramics and the giant magnetostrictive rare-earth-iron alloy
Terfenol-D were prepared by epoxy bonding. The direct and converse
magnetoelectric (ME) effects at and off the mechanical resonant frequency were
characterized and compared to the theoretical modelling. The mechanical resonant
frequency of the composites depended on the sample orientation and the magnetic
DC bias field. In the longitudinal configuration, the resonant frequency shifted
down monotonically with the increasing bias field. When the sample was in the
transverse configuration, the resonant frequency decreased with the increasing
field at first. However, at higher bias, it shifted up with the increasing bias.
A phenomenological model based on the à  E effect of magnetostrictive materials
is proposed to explain the observed phenomen