Deterministic arbitrary switching of polarization in a ferroelectric thin film

R. K. Vasudevan, Y. Matsumoto, Xuan Cheng, A. Imai, S. Maruyama, H. L. Xin, M. B. Okatan, S. Jesse, S. V. Kalinin, V. Nagarajan

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21 Citations (Scopus)

Abstract

Ferroelectrics have been used as memory storage devices, with an upper bound on the total possible memory levels generally dictated by the number of degenerate states allowed by the symmetry of the ferroelectric phase. Here, we introduce a new concept for storage wherein the polarization can be rotated arbitrarily, effectively decoupling it from the crystallographic symmetry of the ferroelectric phase on the mesoscale. By using a Bi5 Ti3 FeO15 -CoFe2 O4 film and via Band-Excitation Piezoresponse Force Microscopy, we show the ability to arbitrarily rotate polarization, create a spectrum of switched states, and suggest the reason for polarization rotation is an abundance of sub-50 nm nanodomains. Transmission electron microscopy-based strain mapping confirms significant local strain undulations imparted on the matrix by the CoFe2 O4 inclusions, which causes significant local disorder. These experiments point to controlled tuning of polarization rotation in a standard ferroelectric, and hence the potential to greatly extend the attainable densities for ferroelectric memories.

Original languageEnglish
Article number4971
Number of pages8
JournalNature Communications
Volume5
DOIs
Publication statusPublished - 18 Sep 2014
Externally publishedYes

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