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)
494 2017-03-21 16:00    Spring 2017: Physics Seminar Serises file
493 2017-03-24 14:30    Topological Dynamics
492 2017-03-24 16:00    Graphene based nano electronics and nano electromechanics; focusing on precise control of nano structures for studying accurate physical properties
491 2017-04-05 12:00    2017년 4월 첫수 융합포럼 개최 안내(물리학과 & 원자력 및 양자공학과 공동 개최)/The First Wednesday Multidisciplinary Forum in April 2017 organized by Dept. of Physics & Dept. of Nuclear & Quantum Engineering file
490 2017-04-06 16:00    For whom the Belle tolls
489 2017-04-27 16:00    반도체 양자점을 이용한 단광자 광원
488 2017-04-28 14:30    Hot electron generation at surfaces and its impact to catalysis and renewable energy conversion
487 2017-04-28 16:00    Carbon nanotubes coupled to superconducting impedance matching circuits
486 2017-05-12 13:30    Topological Dirac insulator
485 2017-06-02 14:30    Quasiparticle Interference and Fourier transform scanning tunneling spectroscopy in WTe2 (Weyl semimetal) file
484 2017-06-02 16:00    Maxwell's demon in quantum wonderland file
483 2017-07-10 16:00    “Intertwined Orders in a Heavy-fermion metal” file
482 2017-07-14 15:00    Chiral anomaly in disordered Weyl semimetals file
481 2017-08-16 16:00    Phonon-driven spin-Floquet valleytro-magnetism file
480 2017-08-31 14:00    “Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals” file
479 2017-09-12 16:00    Exact Solution for the Interacting Kitaev Chain at Symmetric Point file
478 2017-09-13 16:00    An Introduction to Quantum Spin Liquids file
477 2017-09-22 13:00    Superconductor-metal-insulator transition in thin Tantalum films file
476 2017-09-22 14:30    Quantum Electronic Transport in Graphene Hybrid Nanostructures file
475 2017-09-22 16:00    Unexpected Electron-Pairing in Integer Quantum Hall Effect file