Electrical poling below coercive field for large piezoelectricity

Fatigue crack growth in ferroelectric ceramics below the coercive field

Perovskite-type ferroelectric ceramics have found many applications in actuators, sensors and memories. One critical limitation on their performance is due to electric fatigue, which refers to the deterioration of material properties associated with electric cycling. The degradation of electrical properties in ferroelectrics, which appears in the hysteresis loop in the form of a decrease of rem...

Intrinsic ferroelectric coercive field

The Landau-Ginzburg theory of ferroelectricity predicts the intrinsic coercive field for polarization reversal, but the observed extrinsic coercive field is always much smaller as a result of nucleation, dynamic processes not covered by the static theory. We have realized the intrinsic coercive field for the first time, in two-dimensional Langmuir-Blodgett polymer films as thin as 1 nm. The mea...

Piezoelectricity of bone and electrical callus

The year 2012 is the 60th anniversary of the discoveries of the piezoelectricity of bone and electrical callus, which were reported by Dr. Iwao Yasuda of our department for the first time in 1953, only 8 years after the end of World War II. The historians of the Japanese Orthopaedic Association have designated these accomplishments as ‘‘a great and proud Japanese achievement for orthopedics’’. ...

Near-field Raman dichroism of azo-polymers exposed to nanoscale dc electrical and optical poling.

Azobenzene-functionalized polymer films are functional materials, where the (planar vs. homeotropic) orientation of azo-dyes can be used for storing data. In order to characterize the nanoscale 3D orientation of the pigments in sub-10 nm thick polymer films we use two complementary techniques: polarization-controlled tip-enhanced Raman scattering (TERS) microscopy and contact scanning capacity ...

Coercive combined field integral equations