visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2018-06-22 16:00 
연사  
장소 #1323, E6-2 

Physics Seminar

 

 

Tuning functional properties of BiFeO3films using strain and growth chemistry

 

Dr. Daniel Sando

Univ. of New South Wales, Sydney

 

June 22 (Fri.), 04:00 PM

#1323, E6-2

 

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

번호 날짜 연사 제목
공지 2025-02-24 16:00    2025년 봄학기 콜로키움 안내
공지 2025-02-27 16:00    2025년 봄 물리학과 특별세미나 (광학/응집물리 분야)
245 2015-11-10 16:00    Rapid heating of matter using high power lasers
244 2022-11-10 16:00    Probing the Origin of Cosmic Infrared Background and Future Prospects with SPHEREx
243 2023-02-28 11:00    Topotactic redox engineering toward novel material file
242 2018-10-16 10:00    Capturing protein cluster dynamics and gene expression output in live cells file
241 2025-04-29 16:00  Dr. Tokuro Shimokawa (Okinawa Institute of Science and Technology)  Can experimentally-accessible measures of entanglement distinguish quantum spin liquid and random singlet phases? file
240 2018-06-18 10:00    Rydberg electromagnetically induced transparency and microwave-to-optical conversion using Rydberg atoms file
239 2025-05-28 16:00  Dr. Thiago L. M. Guedes (Forschungszentrum Jülich)  Computing the graph-changing dynamics of loop quantum gravity file
238 2019-03-29 16:00    Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM file
237 2023-09-26 16:00    [High Energy Theory Seminar]A new step in interacting dark sector cosmologies
236 2016-03-11 16:00    Jan. Switching handedness of of chiral solitons in Z4 topological insulators
235 2021-04-02 14:30    Quantum computing and entanglement generation using trapped ions and photons
234 2021-05-14 14:30    Electrically tunable spin valve effect in vertical van-der-Waals magnetic tunnel junctions file
233 2015-11-28 10:00    Electron Tunneling Spectroscopy of Single and Bilayer Graphene with Hexagonal Boron Nitride as Tunneling Barrier
232 2022-05-11 16:00    Gravity as a phenomenon in quantum dynamics
231 2022-05-25 16:00    Uncovering New Lampposts for Dark Matter: Continuum or Conformal
230 2019-05-01 16:00    Raman and x-ray scattering study on correlated electron systems: two case examples file
229 2018-04-13 10:00    Quantum meets Mechanics: from Quantum Information to Fundamental Research file
228 2022-09-30 14:30    Putting a spin on the Josephson effect file
227 2022-07-14 15:00    Pure two-dimensional quantum electron liquid and its phase transition
226 2017-11-03 16:00    Expedition to the Kitaev Quantum Spin Liquid: Hunting for Majorana fermions file