Layered perovskites with giant spontaneous polarizations for nonvolatile memories.
A series of titanate-based layered perovskites having large values of the spontaneous polarization P(s) were developed for their applcations to nonvolatile ferroelectric random access memories. Among these, the Nd-modified bismuth titanate [Bi(4-x)Nd(x)Ti(3)O(12) (BNdT)] system exhibited the most remarkable ferroelectric properties. The c-axis oriented BNdT capacitor was characterized by a switchable remanent polarization 2P(r) of over 100 microC/cm(2) and imprinting and fatigue-free behavior. The active Ti site responsible for the giant P(s) was identified with the help of Rietveld analysis, x-ray absorption near-edge structure study, and ab initio quantum computations.
Chon
Uong
U
Department of Materials Science and Engineering, and National Research Laboratory for Ferroelectric Phase Transitions, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of Korea.
Jang
Hyun M
HM
Kim
M G
MG
Chang
C H
CH