摘要:

X-ray diffraction showed that the volume fraction of 90° domains in tetragonalPb(Zr,Ti)O3thin films could be substantially reduced by either hot dc poling or by a bipolar pulsed-field process. In both cases, the (001) Bragg peak increased and the (100) peak decreased. However, ferroelectric hysteresis loops look quite different. Hot dc poling leads to large internal fields and high frozen-in polarisation, whereas pulse treatment removes the voltage shifts. This relaxation of the loop and x-ray diffraction results indicate a liberation of defect-pinned domain walls by removing, reorienting, or randomizing charged defects or defect dipoles. Alignment of defects during hot dc poling contributes to piezoelectric and pyroelectric activities. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121554

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A technique for detecting strain has been demonstrated based on a spin-valve sensor. The 400 Å thick sensor has been integrated onto an atomic force microscope cantilever. An applied strain caused by bending of the cantilever changes the orientation of the free-layer magnetization due to magnetostriction. This in turn results in a change in the electrical resistance because of the giant magnetoresistance effect. With the proper magnetic bias, a base-line strain sensitivity of10−10/Hz1/2has been achieved. The corresponding gauge factor of 150 is roughly1.6×that of similar silicon piezoresistive cantilevers. In the future, one might be able to enhance the sensitivity by another factor of 3–5. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121555

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Using noncontact scanning probe microscopy techniques, dielectric properties were studied on 50-nm-length scales in poly-vinyl-acetate (PVAc) and poly-methyl-methacrylate films. Low-frequency(1/f )fluctuations observed in the measurements, peaked in intensity near the glass transition temperature in PVAc. The noise is shown to arise from thermal dielectric polarization fluctuations. Analysis of this noise provides a noninvasive method of probing equilibrium nanometer-scale dynamical processes in dielectric materials and devices. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121556

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

The operation of the resistively coupled single-electron transistor (R-SET) is studied quantitatively. Due to the Nyquist noise of the coupling resistance, degradation of the R-SET performance is considerable at temperaturesTas small as10−3e2/C(whereCis the junction capacitance) while the voltage gain becomes impossible atT≳10−2e2/C.©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.121557

出版商:AIP    

年代:1998

数据来源: AIP