Higher-order nonlinear dielectric microscopy

Abstract

Articles you may be interested inLateral resolution improvement in scanning nonlinear dielectric microscopy by measuring super-higher-order nonlinear dielectric constants

Effect of the surface adsorbed water on the studying of ferroelectrics by scanning nonlinear dielectric microscopy

“…Even though the sign of the ͑4͒ signal never changed, the specimen was imaged because the signal level of ͑4͒ in the negative domain was smaller than that in the positive domain. We have previously observed this phenomenon in the measurement of a LiNbO 3 single crystal, 5 and consider the cause of this phenomenon to be as follows.…”

“…Thus, higher order nonlinear dielectric imaging has higher resolution and senses at a much shallower depth. 5 There are two types of SNDM, needle-type SNDM, which uses an electropolished tungsten needle as a tip for measuring a large area, and cantilever-type SNDM for measuring a small area with high resolution. In the case of cantilever-type SNDM, to keep in the contact state, we use a feedback circuit containing a laser and photodiode, analogous with contact-mode atomic force microscopy.…”

“…This microscopy can obtain the linear and nonlinear dielectric constant distribution over a dielectric or ferroelectric material surface. [3][4][5] In particular, SNDM reveals the polarization direction at the surface of ferroelectric materials by the observed sign of the odd-rank nonlinear dielectric constant tensor. Moreover, by analyzing different orders of nonlinear dielectric constants, SNDM can measure the material at varying penetration depths.…”

“…Therefore, SNDM is very useful for observing the surface polarization state of ferroelectric materials. 5 To investigate in detail the surface polarization state of ferroelectric materials it is necessary to control the atmosphere and to examine the effect of adsorbed layers (especially adsorbed water) on the SNDM image because these layers are thought to affect the SNDM signal level. When a layer with large linear dielectric constant is adsorbed on the specimen, SNDM has a lower resolution because the electric field just under the tip is broadened and the SNDM also senses the surface as being deeper than reality.…”

Piezoresponse Force Microscopy: A Window into Electromechanical Behavior at the Nanoscale

“…The scanning nonlinear dielectric microscopy approach employs a special resonator probe operating in the microwave frequency range. 51 Point-topoint detection of the local voltageinduced change in the sample capacitance allows nanoscale domain imaging in a surface layer of about 10-nm thick. Given that the width of domain walls in ferroelectrics is typically very small (of the order of 1-3 unit cells), this ferroelectric recording potentially allows extremely high data storage densities, well above that of conventional magnetic recording.…”