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Characteristics of $(Pb_{1-x}La_x)(Zr_{0.5}Ti_{0.5})O_3$ thin films as a function of La content  

Jang, Nak-Won (한국해양대학교 전기전자공학부)
Lee, Seong-Hwan (위덕대학교 에너지전기공학부)
Yi, Dong-Young (위덕대학교 에너지전기공학부)
Kim, Dong-Hun (경북대학교 전자전기컴퓨터학부)
Publication Information
Journal of Advanced Marine Engineering and Technology / v.30, no.8, 2006 , pp. 894-900 More about this Journal
Abstract
The electrical characteristics associated with crystal structure changes as a function of La content for $(Pb_{1-x}La_x)(Zr_{0.5}Ti_{0.5})O_3$ thin films were investigated for applications in memory capacitors. Tetragonality of PLZT films decreased with increasing La content. Thin films with La $\geq$ 20 mol% were found to be cubic. Films with La $\geq$ 12 mol% exhibited broader dielectric peaks compared to those of bulk ceramics and behaved as relaxer ferroelectrics. Tetragonal PLZT film with 12 mol% La had a dielectric constant maximum of 1330 at room temperature and a charge storage density of ${\sim}18{\mu}C/cm^2$ at 5 V. Decrease in coercive field and remnant polarization with increase in La content were resulting from less dipolar response caused by the decreased crystal anisotropy. The leakage current densities $<10^{-8}A/cm^2$ up to 5 V bias voltage were observed for the films with La $\geq$ 14 mol%.
Keywords
Ferroelectric material; Hysteresis loop; Pseudocubic; Pulsed laser deposition; Tetragonality;
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