2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009;
Pittsburgh, Pennsylvania
Session X28: Focus Session: Magnetoelectric Coupling in Multiferroic Systems
2:30 PM–5:18 PM,
Thursday, March 19, 2009
Room: 330
Sponsoring
Units:
FIAP DMP
Chair: Gopalan Srinivasan, Oakland University
Abstract ID: BAPS.2009.MAR.X28.1
Abstract: X28.00001 : Quantitative investigation of magnetoelectric coupling in various forms of multiferroics*
2:30 PM–3:06 PM
Preview Abstract
Abstract
Author:
Kee Hoon Kim
(Seoul National University)
Magnetoelectric susceptibility (MES) is probably the most direct
way of
estimating the magnitude of magnetoelectric coupling in many
forms of
magnetoelectric and/or multiferroic materials. Historically, the
MES has
been measured in numerous existing magnetoelectric materials in
broad field,
frequency, and temperature ranges and their MES values have been
tabulated
[1]. With growing interest worldwide toward applications of
multiferroics
for novel memory and sensor devices, however, there have been
ever-increasing demands to measure quantitatively the MES of
multiferroic
thin films. Yet, the measurements of thin film MES become
challenging in
spite of its large MES value because the magnetoelectric voltages,
proportional to the film thickness, usually get too small to be
measured
reliably. Herein, we introduce a highly sensitive magnetoelectric
susceptometer that can detect the charge variation down to $\sim
$10$^{-17}$C in a few gauss oscillating magnetic field. Using
this specific
setup, we could measure the MES of multiferroic thin films or single
crystals with unprecedented accuracy and sensitivity in cryogenic
(down to 2
K) and magnetic field (up to 9 T) environments. In this talk, we
summarize a
number of key results based on this technique; (1) MES of a 300 nm
BiFeO$_{3}$-CoFe$_{2}$O$_{4}$ nanopillar structure as well as
those of a 250
nm BiFeO$_{3}$ film and of a BiFeO$_{3}$ single crystal. (2) MES of
(Pb,Zr)TiO$_{3}$-NiFe$_{2}$O$_{4}$ nanocomposite films, and (3)
temperature-
and field-dependent MES in representative multiferroic
crystals/films
including TbMn$_{2}$O$_{5}$ , GaFeO$_{3}$, and Cr$_{2}$O$_{3}$. In
particular, we demonstrate that the MES of the film with the
nanopillar
structure is enhanced by approximately one order of magnitude
reaching
2×10$^{-10}$ s/m at room temperature, compared with those of a pure
BiFeO$_{3}$ film and a single crystal. Furthermore, based on
detailed field
and temperature dependent MES studies, we show that
magnetoelectric coupling
in TbMn$_{2}$O$_{5}$ has been mediated and amplified by the large
magnetoelastic effect.
\\[4pt]
[1] G. A. Smolenskii and I. E. Chupis, Sov. Phys. Usp. 25, 475
(1982); F. W.
Hehl \textit{et al.} Phys. Rev. A 77, 022106 (2008).
*In close collaboration with Yoon Seok Oh, S. Crane, I. Takeuchi, R. Ramesh, T. W. Noh, S.-W. Cheong, and Albert Migliori.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.X28.1