Bulletin of the American Physical Society
2008 APS March Meeting
Volume 53, Number 2
Monday–Friday, March 10–14, 2008; New Orleans, Louisiana
Session W37: Focus Session: Multiferrocity in BiFeO$_3$-based films |
Hide Abstracts |
Sponsoring Units: DCMP Chair: Craig Fennie, Argonne National Laboratory Room: Morial Convention Center 229 |
Thursday, March 13, 2008 2:30PM - 2:42PM |
W37.00001: First-principle calculations of electronic structure of bismuth ferrate and manganate with the mullite structure Jen-Chang Chen, Ching-Ming Wei We applied ab initio total-energy calculation to study the electronic structure of Bi$_2$Fe$_4$O$_9$ and Bi$_2$Mn$_4$O$_{10}$ single crystals. Both crystals are orthorhombic with the centro-symmetric structure and belong to the mullite-type material. Most of bismuth-based oxides exhibit good ferroelectricity, pyroelectricity and piezoelectricity. However, little researches of electronic structure and properties have been done on the bismuth ferrate and bismuth manganate. In this study, the band structure, density of state, partial density of state and magnetic moment of both bismuth ferrate and bismuth manganate at zero Kevin were calculated. The effect of Fe and Mn atom within the structure were discussed. The phase stability of these two crystals was also examined. [Preview Abstract] |
Thursday, March 13, 2008 2:42PM - 2:54PM |
W37.00002: The structural, magnetic, and electric properties of Sr and Ca-doped BiFeO$_{3}$ films. Chan-Ho Yang, M. Huijben, Y.-H. Chu, L.W. Martin, M. Holcomb, R. Ramesh, M. Chi, N. Browning Many perovskite oxides, as holes are doped, exhibit unusual physical phenomena such as superconductivity, colossal magnetoresisitance, metal-insulator transition, and charge ordering. We are expoloring the consequences of hole doping into a well known multiferroic, the antiferromagnetic ferroelectric, BiFeO$_{3}$. In this presentation, the systematic investigation on structural, electric, and magnetic properties will be presented for nominally hole-doped BiFeO$_{3}$ obtained by partially substituting the Bi ions by divalent ions (such as Ca and Sr). The parent BiFeO$_{3}$ is unique single-compound multiferroic material with ferroelectricity and magnetic ordering at room temperature, has polarization along [111] direction and is a G-type antiferromagnet. The divalent ion doping weakens the ferroelectric properties but improves magnetization owing to cluster-glass-like magnetism. We will discuss the magnetic properties based on superexchange mechanism. The structural characterization by X-ray diffraction, scanning microscopy and TEM will be presented. The SQUID and the dielectric constant measurements as a function of magnetic field and temperature will be also reported. [Preview Abstract] |
Thursday, March 13, 2008 2:54PM - 3:06PM |
W37.00003: Phase diagram for Bi1-xCaxMnO3 (x $<$ 0.4) Yuhai Qin, Trevor Tyson, Sang-Wook Cheong, Xiao-nong Xu The multiferroic BiMnO3 system, in which ferroelectronic and ferromagnetic orders can coexist, has attracted much research work in the past years for its potential technological applications. For the more general system Bi1-xCaxMnO3, the phase diagram for the Ca rich region (x $>$ 0.4) has been established[1]. In order to understand the multiferroic behavior near the x=0 system, the hole-doped region (0$<$x$<$0.4) was investigated. We have completed the magnetic, transport, and structural phase diagram of Bi1-xCaxMnO3, by performing detailed structural (XRD and XAFS), magnetization (ZFC/FC) and electrical measurements on Bi1-xCaxMnO3 (0$<$x$<$0.4), showing the transition form the highly distorted monoclinic phase to the orthorhombic phase. This work is supported by NSF DMR-0512196 and DOE Grant DE-FG02-07ER46402. [1] H. Woo, et al, Phys. Rev. B: Condensed Matter and Materials Physics 63, 134412/1 (2001). [Preview Abstract] |
Thursday, March 13, 2008 3:06PM - 3:18PM |
W37.00004: Combinatorial discovery of morphotropic phase boundary in a lead-free high $T_{c}$ piezoelectric perovskite Bi$_{1-x}$(RE)$_{x}$FeO$_{3}$ S. Fujino, D. Kan, A. Varatharajan, C.J. Cheng, V. Nagarajan, M. Murakami, S.-H. Lim, D. Hunter, C.J. Fennie, L. Salamanca-Riba, M. Wuttig, I. Takeuchi We have recently discovered a morphotropic phase boundary (MPB) in Bi$_{1-x}$Sm$_{x}$FeO$_{3}$ which has a simple perovskite structure. We have systematically investigated compositionally varied Sm doped BiFeO$_{3}$ thin films using the combinatorial approach and found that ferroelectric properties and piezoelectric properties show pronounced enhancement at the MPB. The samples were fabricated by combinatorial pulsed laser deposition on SrTiO$_{3}$ (001) substrates with a SrRuO$_{3}$ buffer layer. The boundary is a rhombohedral to pseudo-orthorhombic structural transition which exhibits a ferroelectric to antiferroelectric transition at approximately Bi$_{0.86}$Sm$_{0.14}$FeO$_{3}$ with intrinsic d$_{33}$ comparable to those of PbZr$_{0.52}$Ti$_{0.48}$O$_{3}$ thin films. Transmission electron microscopy (TEM) reveals presence of nanodomains at the MPB. TEM also reveals onset and formation of antiferroelectric domains as the composition is swept near the MPB, where electron diffraction patterns show systematic structural tilt transitions of the system as a function of Sm doping. Finally, we report on structural transitions and ferroelectric properties in other Bi$_{1-x}$(RE)$_{x}$FeO$_{3}$ systematically studied by the composition spread technique. This work is supported by NSF MRSEC, ARO, and the W. M. Keck Foundation. Research at UNSW is supported by DEST Australia, Australian Research Council Grant DP 0666231 and ARNAM Travel Grant. [Preview Abstract] |
Thursday, March 13, 2008 3:18PM - 3:30PM |
W37.00005: The effect of structural and chemical perturbations in multiferroic BiFeO$_{3}$ epitaxial films Dae Ho Kim, H.N. Lee, M. Varela, H.M. Christen, M.D. Biegalski, C.J. Callender, D.P. Norton The compatibility between the lone-pair driven ferroelectric distortion and antiferromagnetic order in BiFeO$_{3}$ attracts a lot of attention. A detailed understanding of ferroelectric properties in BiFeO$_{3}$ is gained by investigating the effect of structural/chemical perturbations in strained epitaxial films with chemical modifications. Our work shows that the ferroelectric polarization along [111] exhibits weak dependency on epitaxial strain on a (001) substrate. To examine the role of distortions induced by magnetic ions, we have grown BiFe$_{1-x}$Cr$_{x}$O$_ {3}$ epitaxial films and observed a ferroelectric to antiferroelectric transition with increasing the Cr content. Furthermore, epitaxial films of Bi$_{1-y}$Ba$_{y}$FeO$_{3}$ were grown to investigate the effect of structural variation in connection with change in the valence of Fe ion. The results reveal a high stability of the ferroelectric distortion in epitaxial BiFeO$_{3}$ films. [Preview Abstract] |
Thursday, March 13, 2008 3:30PM - 3:42PM |
W37.00006: Structural, electrical and magnetic properties of Bi(Fe$_{x}$,Ti$_{1-x})$O$_{3}$ thin films N.M. Murari, R. Melgarejo, R. Thomas, R.S. Katiyar Multiferroic materials have recently seen a surge of research activities due to its applications in the memory, spintronics, sensors devices and micro mechanical systems (MEMS). BiFeO$_{3}$ is a naturally occurring multiferroics. However, the large leakage current is a concern for practical applications and substitution at Bi and Fe is commonly employed to circumvent this problem. Here, Fe substitution by Ti is considered for this purpose. Thin films on Pt/Ti/SiO$_{2}$ /Si were grown by chemical solution deposition (CSD) and characterized for structure and symmetry by XRD and Raman scattering, surface morphology by AFM, dielectric properties by impedance analyzer, and the leakage current by I-V measurements. Magnetic (M-H) and electric (P-V) hysterisis loops were also studied. Variation of dielectric constant ($\varepsilon _{r})$ and loss tangent (tan$\delta )$ with temperature, frequency and temperature were systematically studied. Further, the effect of Ti substitution on the electrical properties will be presented. [Preview Abstract] |
Thursday, March 13, 2008 3:42PM - 3:54PM |
W37.00007: Piezoelectricity and structure of epitaxial ferroic thin films at high electric fields Alexei Grigoriev, Ribecca Sichel, Ho Nuyng Lee, Chang-Beom Eom, Zhonghou Cai, Eric C. Landahl, Bernhard Adams, Eric M. Dufresne, Paul G. Evans With mastering the techniques to grow nearly perfect epitaxial thin oxide films, there are emerging opportunities to control the structure and properties of oxide materials using extremely high electric fields. To unveil the piezoelectric and structural properties of Pb(Zr,Ti)O3 and BiFeO3 epitaxial thin films at electric fields which are a few times stronger than the low-frequency dielectric breakdown field, we employed time-resolved structural measurements synchronized with electric field pulses of a nanosecond duration. At these extreme fields we measured record-high piezoelectric strains and explored nonlinearities in piezoelectric responses predicted to occur due to the changes in interatomic interactions. [Preview Abstract] |
Thursday, March 13, 2008 3:54PM - 4:06PM |
W37.00008: Giant Polarization Rotation in BiFeO3/SrTiO3 Thin Films. M.C. Langner, Y.H. Chu, L.M. Martin, M. Gajek, R. Ramesh, J. Orenstein We use optical second harmonic generation to probe dynamics of the ferroelectric polarization in (111) oriented BiFeO3 thin films grown on SrTiO3 substrates. The second harmonic response indicates 3m point group symmetry and is consistent with a spontaneous polarization normal to the surface of the film. We measure large changes in amplitude and lowering of symmetry, consistent with polarization rotation, when modest electric fields are applied in the plane of the film. At room temperature the rotation is an order of magnitude larger than expected from reported values of the dielectric constant and increases further (as 1/T) as temperature is lowered. We propose a substrate interaction model to explain these results. [Preview Abstract] |
Thursday, March 13, 2008 4:06PM - 4:18PM |
W37.00009: ABSTRACT WITHDRAWN |
Thursday, March 13, 2008 4:18PM - 4:54PM |
W37.00010: Exchange biasing with multiferroic: electric field effects on magnetic and magnetotransport properties Invited Speaker: Room-temperature multiferroic materials are scarce and display a weak magnetoelectric coupling and thus huge difficulties exist for controlling the magnetic state by using an electric field or viceversa. A possible alternative to circumvent this limitation is to exploit the clamping of ferroelectric and antiferromagnetic domains in biferroic materials and use a suitable exchange-bias existing with ferromagnetic materials to tune the magnetic response of the ferromagnet. In this presentation we shall overview recent experiments on exchange-biasing using hexagonal YMnO$_{3}$ biferroics and Permalloy as a soft-ferromagnet. Exchange-bias on ferromagnetic materials is most commonly evidenced by their magnetic response, although magnetotransport measurements are also very adequate to monitor the exchange bias. We will present and discus first how exchange-bias is manifested and monitored. Next, we will describe the effects of an electric field, biasing the ferroelectric (and antiferromagnetic) epitaxial layer, on the exchange bias. We will show that under appropriate conditions, magnetization can be switched by application of a suitable electric field. We will discuss the significance of the results with particular attention to role of current leakages across the ferroelectric. \newline \newline In collaboration with X. Mart\'{\i}, Institut de Ci\`{e}ncia de Materials de Barcelona-CSIC, Spain; V. Laukhin, Institut de Ci\`{e}ncia de Materials de Barcelona-CSIC and Institut Catal\`{a} de Recerca i Estudis Avan\c{c}ats (ICREA), Barcelona, Catalonia, Spain; V. Skumryev, Institut Catal\`{a} de Recerca i Estudis Avan\c{c}ats (ICREA) and Departament de F\'{\i}sica, Universitat Aut\`{o}noma de Barcelona, Spain; D. Hrabovsky and F. S\'{a}nchez, Institut de Ci\`{e}ncia de Materials de Barcelona-CSIC, Spain; M. Varela, Departament de F\'{\i}sica Aplicada i \`{O}ptica, Universitat de Barcelona, Spain; U. L\"{u}ders and J.F. Bobo, LNMH ONERA-CNRS, France. [Preview Abstract] |
Thursday, March 13, 2008 4:54PM - 5:06PM |
W37.00011: Investigation of the electrical switching of magnetization through exchange interactions with a magnetoelectric multiferroic Alfred Lee, Alex de Lozanne, Ying-Hao Chu, Lane W. Martin, Mikel Barry, Qian Zhan, Pei-Ling Yang, Kilho Lee, Z. Q. Qiu, R. Ramesh The coupling between antiferromagnetic (AF) and ferromagnetic (FM) ordering at an interface between the two types of materials has been well established and provides the basis for modern day hard drives.~ BiFeO$_{3 }$is a magnetoelectric multiferroic material which shows coupling between ferroelectric (FE) and AF phases.~ The Curie and Ne\'{e}l temperatures are $\sim $820 and 370\r{ }C, respectively, permitting room temperature operation.~ Manipulation of the FE ordering via external electric fields affects the AF ordering which in turn permits control over the magnetization of an adjacent FM material.~ We present the results of our investigation into the control of magnetic domains using electric fields.~ The object of investigation is a multilayer film of Co$_{0.9}$Fe$_{0.1}$/BiFeO$_{3}$/SrRuO$_{3}$/SrTiO$_{3}$(001) patterned into islands.~ A magnetic force microscope is used both to image the magnetic domains and to apply the potential across the film. [Preview Abstract] |
Thursday, March 13, 2008 5:06PM - 5:18PM |
W37.00012: Anisotropic photo-control of spontaneous polarization in BiFeO$_{3}$ thin films: Indications of photo-assisted magnetoelectric effect D.S. Rana, I. Kawayama, H. Murakami, M. Tonouchi The terahertz (THz) emission from multiferroic BiFeO$_{3 }$(BFO) due to ultra-fast depolarization of electric order helps in evaluating its ferroelectric behavior [1]. In this work, we investigate THz-emission in BFO films on (LaAlO$_{3})_{0.3}$(Sr$_{2}$AlTaO$_{6})_{0.7}$ (LSAT) substrates along $(100)$, $(110)$ and $(111) $directions. THz emission amplitude (E$_{THz})$ and its electric field dependence are similar in BFO $(100)$ and BFO $(110)$; E$_{THz}$ as function of electric field translates to ferroelectric-like hysteresis loop, and sign and amplitude of THz-emission are commensurate with the applied electric field. On the contrary, in BFO $(111)$ the hysteretic loop is absent, E$_{THz}$ varies linearly with electric field and the polarity of THz-emission is opposite to that of the electric field. These results suggest that THz-emission is mainly a result of ultrafast depolarization but with a superimposed character of ultrafast reorientation or demagnetization of antiferromagnetic (AFM) order. Though AFM order in BFO makes the determination of magnetoelectric (ME) coupling rather difficult, the photo-assisted electric field control of AFM order shown in the present work is suggestive of photo-assisted ME effect. 1. K. Takahashi \textit{et al.}, Phys. Rev. Lett. 96, 117402 (2006). [Preview Abstract] |
Thursday, March 13, 2008 5:18PM - 5:30PM |
W37.00013: Measurements of Bandgap of Epitaxial BiFeO$_{3}$ Films by UV-VIS Absorption and Cathodoluminescence Spectroscopies A.J. Hauser, J. Zhang, L. Mier, R. Ricciardo, P.M. Woodward, T.L. Gustafson, L.J. Brillson, F.Y. Yang We report measurements of the bandgap of pure-phase epitaxial BiFeO$_{3}$ thin films on (001)-oriented SrTiO$_{3}$ substrates, via UV-VIS absorption and cathodoluminescence (CL) spectroscopies. 70 nm thick BiFeO$_{3}$ films were grown using ultrahigh vacuum RF magnetron sputtering at substrate temperatures between 500 \r{ }C and 600 \r{ }C. X-ray diffractometry shows that samples grown in this temperature range are epitaxial and pure-phase. UV-VIS absorption spectra show a consistent bandgap of 2.5 $\pm $ 0.03 eV for all growth temperatures. A small tail in the UV-VIS absorption spectra just below the band gap extends down to 2.2 eV, indicating some electronic states within the bandgap. The bandgap was confirmed via CL measurements, where a bandgap of 2.46 $\pm $ 0.01 eV was obtained for samples at growth temperatures of 550 \r{ }C and 600 \r{ }C. To our knowledge, this report is the first sdetailed measurement of electronic band and defect structure for epitaxial BiFeO$_{3}$ films and confirms theoretical predictions. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700