장소 | #1323, E6-2 |
---|---|
일시 | June 22 (Fri.), 04:00 PM |
연사 | Dr. Daniel Sando |
Physics Seminar
“Tuning functional properties of BiFeO3films using strain and growth chemistry”
Univ. of New South Wales, Sydney
Abstract:
Multiferroics – materials with coexisting ferroic orders such as ferroelectricity and (anti)-ferromagnetism – are presently under intense study by virtue of their promise in next-generation data storage devices. Bismuth ferrite (BiFeO3– BFO) is one of the very few that orders above room temperature. In the bulk, BFO is rhombohedral (R), and in thin films [1] its properties are sensitive to strain [2,3]. The discovery of the epitaxially-stabilized “super tetragonal phase” of BFO (T-BFO) [4] incited a flurry of research activity focused on understanding the phase transition and its possible functionalities [5]. T-BFO is also multiferroic, with large ferroelectric polarization and antiferromagnetic order [4], and the strain relaxation-induced T/R phase mixtures and their exceptional piezoelectric responses [6] continue to intrigue and motivate researchers. A particularly important characteristic of this phase mixture is the interconversion between the R,T phases with an applied electric field [6]. Since the oxygen configuration of the R and T polymorphs is different [5], the electronic, magnetic, and optical properties can thus be dynamically modulated. An additional rather crucial (and thus far underexplored) aspect of mixed R/T BFO is the role of chemistryin the formation of the metastable T-phase. Since T-BFO is typically fabricated by pulsed laser deposition, growth parameters can be used as a strong handle to tailor film properties and functionalities.
Here I will describe our work on understanding the influence of strain and growth conditions on the optical, magnetic, and ferroelectric properties of BFO films. I will also show that by precisely controlling fabrication conditions, the formation of the mixed R/T phases in BFO films can be completely suppressed for thicknesses above 70 nm. Such an intriguing result is useful for applications where thicker pure T-BFO films are needed, such as for measuring the expected giant polarization, or for precisely controlling the proportions of the various phases. Finally, through analysis of a large set of epitaxial films, it will be shown that the optical band gap of BFO is rather insensitive to a host of growth and processing parameters [7]. Combined with the numerous other functionalities of this material, one can envisage multifunctional devices, for example, that harvest mechanical and solar energy, or to enhance magnetoelectric coupling at these multiferroic phase boundaries.
References
[1] Sando et al., J. Phys: Condens. Matt. 26, 473201 (2014).
[2] Infante et al., PRL 105, 057601 (2010).
[3] Sando et al., Nat. Mater. 12, 641 (2013).
[4] Bea et al., PRL 102, 217603 (2009).
[5] Sando et al., Appl. Phys. Rev. 3, 011106 (2016).
[6] Zeches et al., Science 326, 977 (2009).
[7] Sando et al., Adv. Opt Mater. 6, 1700836 (2018).
Department of Physics, KAIST
댓글 0
번호 | 일시 | 장소 | 연사 | 제목 |
---|---|---|---|---|
180 | July 13, 2018 at 14:00 | Room 5318, KAIST Natural Sciences Lecture Hall(E6). | Prof. Ian Lewis (The University of Kansas, Department of Physics & Astronomy) | Loop Induced Single Top Partner Production and Decay at the LHC |
179 | July 2, 2020 (Thursday) | Zoom Video Conference Seminar | Dr. Emmanuel Flurin (CEA Saclay) |
An irreversible qubit-photon coupling for the detection of itinerant microwave photons
![]() |
178 | July 2. 2018 (Monday) 3:00 PM | Seminar Room (C303), Creation Hall (3F), KAIST Munji Campus | Dr. Peter Winter (Argonne National Laboratory) |
High Precision Magnetic Field Measurement for the Muon g-2 Experiment
![]() |
177 | July 21 - August 2 | E6-2,# 5318 | Junmou Chen/Thomas Flacke/Kaoru Hagiwara/Junichi Kanzaki/Chris Kelso/Jeong Han Kim/Kyoungchul Kong/Gabriel Lee/Hye-Sung Lee/Ian Lewis |
Challenges and Opportunities in Theoretical Particle Physics 2019
![]() |
176 | July 25(Thur.),4:00PM | E6-2, #1323 | Prof.Bohm-Jung Yang |
Band topology of twisted bilayer graphene
![]() |
175 | July 26, 2018 at 14:00 | Room 5318, KAIST Natural Sciences Lecture Hall(E6). | Manki Kim (Department of Physics, Cornell University) |
Inflation in String Theory and Backreaction
![]() |
174 | July 27, 2018 at 15:00 | Room 5318, KAIST Natural Sciences Lecture Hall(E6). | Dr. Hyejung Kim(Technische University Dresden) |
Muon g-2 in the 2HDM and MSSM: comprehensive numerical analysis and absolute maxima
![]() |
173 | July 30 (Tue), 4:00 PM | #1323, E6-2 | Dr. Mingu Kang |
Dirac fermions and flat bands in correlated kagome metals
![]() |
172 | July 31(Wed.)/ 16:00 | E6-2, #1323 | Dr. Ivan Borzenets |
Features of ballistic superconducting graphene
![]() |
171 | July 8(Mon), 14:00 | E6, #1322 | T. L. M. Guedes (Univ. of Konstanz) |
Ultrabroadband squeezed pulses and their relation to relativity
![]() |
170 | July 9 (Mon.), 14:00 PM | #1323, E6-2 | Prof. Cesar A. Hidalgo, MediaLab, MIT |
The principles of collective learning
![]() |
169 | July. 14 (Fri.), 3:00 PM | #1323 (E6-2. 1st fl.) | Dr. Jun Hyun Lee / University of Maryland |
Chiral anomaly in disordered Weyl semimetals
![]() |
168 | Jun 1 (Wed) 4 PM | #1323(E6-2 1st fl.) | Kil-Byoung Chai, Caltech | Laboratory experiments relevant to mesospheric clouds, Saturn’s rings & astrophysical jets |
167 | Jun 22(Tue) 17:00 | Zoom webinar | Wei Han (Peking University, China) |
Spintronics meets Quantum Materials
![]() |
166 | Jun 24 (Mon) 11:00 | E6-2, #1323 | Dr. Henning Schomerus |
Topological photonic anomalies
![]() |
165 | Jun 28, 14:00 | E6-2, #1322 | Dr. Bongjae Kim, Dr. Sooran Kim, Dr. Jeongwoon Hwang |
1st Research-exchange meeting of computational material physics
![]() |
164 | Jun 8 (Tue), 10:00 AM | Zoom webinar | Toshihiko Baba (Yokohama National University, Japan) |
Photonic crystal devices for sensing
![]() |
163 | Jun. 01 (Fri.), 11:00 AM | E6-2. 1st fl. #1323 | Dr. Seung Sae Hong |
Topological phases in low-dimensional quantum materials
![]() |
162 | Jun. 1(Wed) 10:30 AM | BK21 Conference Room (#1318, E6-2) | Dr. Noriaki Horiuchi, Editor, Nature Photonics | Welcome to Nature Photonics |
161 | Jun. 11 (Fri.), 02:30 PM | Online seminar | Dr. Jin Woong Cha(KRISS) |
Engineering sound waves and vibrations in multi-mode nanomechanical systems
![]() |