visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2018-06-22 16:00 
일시 June 22 (Fri.), 04:00 PM 
장소 #1323, E6-2 
연사 Dr. Daniel Sando 

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 장소 제목
371 2022-05-18 16:00  E6-2. #1323 & Zoom  Geometry, Algebra, and Quantum Field Theory
370 2022-05-16 16:00  E6, #1501  Design synthetic topological matter with atoms and lights
369 2022-05-13 16:00  자연과학동(E6-2) 1st fl. #1323  High-fidelity iToffoli gate for fixed-frequency superconducting qubits file
368 2022-05-13 14:30  Zoom webinar  Topological Superconducting Spintronics Towards Zero-Power Computing Technologies file
367 2022-05-12 16:00  E6-2. #1323 & Zoom  New frontiers of electroweak physics at the LHC
366 2022-05-11 16:00  E6-2. #1323 & Zoom  Gravity as a phenomenon in quantum dynamics
365 2022-05-10 16:00  E6 1323  (광학분야 특별세미나)Testing quantum thermodynamics using quantum optics
364 2022-05-09 16:00  E6, #1501  Searching for new electronic properties in correlated material flatland
363 2022-05-02 16:00  E6, #1501  What can we learn from the history of science and technology?(우리말강의)
362 2022-04-28 16:00  E6 1323  (광학분야 특별세미나)Adiabaticity and symmetry in optical waveguide design
361 2022-04-25 16:00  E6, #1501  Ultrafast electron beam, a tool to explore the nanoscopic world of materials(우리말강의)
360 2022-04-15 11:00  Online seminar  (응집물리 세미나) First-principles studies of polar oxides and their applications file
359 2022-04-14 16:00  E6 1323  (광학분야 특별세미나)Holographic tomography of dielectric tensors at optical frequency
358 2022-04-13 10:30  E6 #1323/zoom  Harnessing topology and correlations from singularities in 3d-kagome metals
357 2022-04-11 16:00  E6, #1501  Emergence of Statistical Mechanics in Quantum Systems
356 2022-04-08 11:00  E6-1 #1323  (응집물리 세미나) Flat-surface-assisted physical phenomena occurring in single crystal metal thin film file
355 2022-04-04- 16:00  E6, #1501  New paradigms in Quantum Field Theory
354 2022-04-01 16:00  Zoom webinar  High-field Electron Transport and Interaction Induced Phenomena in 2D Materials file
353 2022-03-31 16:00  online  (광학분야 특별세미나)Ultrafast time-resolved spectroscopy in topological materials
352 2022-03-31 10:00  E6 #1501/zoom  Weiss fields for Quantum Spin Dynamics file