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
504 2016-05-16 16:00  #1323(E6-2, 1st Fl.)  Tuning microwave cavities with biased nonlinear dielectrics for axion searches
503 2018-10-12 14:30  E6-2. 1st fl. #1323  Quantum Advantage in Learning Parity with Noise file
502 2023-04-04 16:00  Room 2501, KAIST Natural Sciences Lecture Hall(E6)  Chiral Magnetism: A Geometric Perspective
» 2018-06-22 16:00  #1323, E6-2  Tuning functional properties of BiFeO3 films using strain and growth chemistry file
» 2018-06-22 16:00  #1323, E6-2  Tuning functional properties of BiFeO3 films using strain and growth chemistry file
499 2018-09-05 16:00  #1323, E6-2  Shining a light on fractional excitations file
498 2022-03-18 11:00  Online seminar  (응집물리 세미나) Illuminating exotic states of matter: Raman spectroscopy as an experimental tool to characterize quantum spin liquids file
497 2021-03-02 16:00  Online  Sensitive terahertz detection with graphene-based transistors file
496 2020-11-20 16:00  Online  Coherent control of field gradient induced quantum dot spin qubits
495 2016-11-04 15:00  E6-2. #1323(1st fl.)  Quantum information experiments using few electron spins in semiconductors
494 2022-01-17 14:00  E6-2 Room 2502  Five Lectures on Observational Probes of Dark Energy file
493 2018-11-09 16:00  E6-2. 1st fl. #1323  Quantum sensing and imaging with diamond defect centers for nano-scale spin physics file
492 2022-11-18 16:00  E6-2. 1st fl. #1323 & Zoom  Qubits, new experimental tools for physics file
491 2020-11-20 14:30  Online  Lumpy Cooper pairs in an iron-based superconductor
490 2017-07-10 16:00  Jul. 10th (Mon), 4pm  “Intertwined Orders in a Heavy-fermion metal” file
489 2022-05-25 14:00  E6 Room(#2501)  Atomic-level insights into ferroelectric switching and preferred orientation of ultrathin hafnia file
488 2023-04-28 11:00  E6 #1323  Tkachenko wave: From the modern field theory viewpoint
487 2018-10-18 10:00  #1323, E6-2  Understanding membrane protein folding using single-molecule force techniques file
486 2023-07-19 16:00  E6-2, #1323  [High-Energy Theory Seminar]Deriving the Simplest Gauge-String Duality
485 2023-03-02 11:00  E6-2, #1322  Probing Anomalies of Non-Invertible Symmetries with Symmetry TFTs