Measurement of Piezoelectric Transverse and Longitudinal Displacement with Atomic Force Microscopy for PZT Thick Films
- PDF / 247,337 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 59 Downloads / 229 Views
Measurement of Piezoelectric Transverse and Longitudinal Displacement with Atomic Force Microscopy for PZT Thick Films. Yuta Kashiwagi1, 2, Takashi Iijima2, Toru Aiso3, Takashi Yamamoto4, Ken Nishida4, Hiroshi Funakubo5, Takashi Nakajima1 and Soichiro Okamura1 1
Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan National Institute of Advanced Industrial Science and Technology, AIST Tsukuba West, 16-1 Onogawa, Tsukuba, Ibaraki 305-8569, Japan 3 Toyo Corporation, 1-1-6 Yaesu, Chuo-ku, Tokyo 103-8284, Japan 4 National Defense Academy, 1-10-20 Hashirimizu, Yokosuka, Kanagawa 239-8686 Japan 5 Tokyo Institute of Technology, 4259 Nagatsuda, Midori-ku, Yokohama 226-8502, Japan 2
ABSTRACT The actual transverse and longitudinal displacement of PZT thick film was measured using a newly developed atomic force microscopy (AFM). The AFM is attached a feedback circuit named “torsion feedback”. The torsion and Z-height feedback circuits control an AFM cantilever to follow piezoelectric deformation of the sample. To measure transverse displacement, the cantilever contacts the edge of sample. The transverse displacement is determined from the torsion feedback signal absolutely. To measure longitudinal displacement, the cantilever contacts the center of sample. The longitudinal displacement is determined from Z-height feedback signal absolutely. A 5-Pm-thick PZT film was prepared on Pt/Ti/SiO2/Si substrates. The film sample was shaped square pillar. The side electrode length (L) of square pillar shaped sample was ranged from 1000 Pm to 10 Pm. The relation between side electrode length and the transverse or the longitudinal displacements were investigated. With decreasing L, the transverse displacement decreased nonlinearly, and the longitudinal displacement increased nonlinearly. The finite element method (FEM) simulation suggests that the substrate clamped PZT film behaved nonlinearly. The effective -d31 and d33 were calculated from the measured displacement, and these values increase with decreasing L. The effective d33 and -d31 showed correlation, and the ratio was d33 : -d31 = 5.3 : 1 , whereas the bulk ratio is d33 : -d31 = 2.4 : 1. This result suggests that the substrate clamping effect of the transverse displacement was larger than that of the longitudinal displacement. INTRODUCTION Piezoelectric materials show the generation of the electric polarization when they are strained and this effect is called direct effect. On the other hand, the piezoelectric materials also show the generation of the strain directly proportional to an applied field and this effect is called converse effect. For poled piezoelectric ceramics, the converse piezoelectric constants, [dij], is usually treated as 2nd rank matrix because of symmetry of crystal. The d31 is the coefficient relating the electric filed along the polar axis to the strain perpendicular to the field, while the d33 is corresponding coefficient for both strain and the field along the polar axis. [1][2] For piezoelectric films, the electric field directi
Data Loading...
