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)
394 2019-04-19 16:00    Graphene and hBN heterostructures file
393 2019-04-23 16:00    From Mott physics to high-temperature superconductivity file
392 2019-04-26 16:00    Robust Quantum Metrology using Strongly Interacting Spin Ensembles and Quantum Convolutional Neural Network file
391 2019-05-01 16:00    Raman and x-ray scattering study on correlated electron systems: two case examples file
390 2019-05-02 16:00    Anomalous optical properties of halide perovskites file
389 2019-05-03 11:00    Exotic Magnetism file
388 2019-05-08 16:00    Imaging valley dependent electron transport in 2D semiconductors file
387 2019-05-09 16:00    Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
386 2019-05-21 16:00    Classification of flat bands according to the band-crossing singularity of Bloch wave functions file
385 2019-05-24 16:00    Infrared spectroscopy study on metal-insulator transitions in layered perovskite iridates file
384 2019-05-30 16:00    Tuning the excitonic properties of semiconductors with light-matter interactions file
383 2019-05-31 11:00    Cavity QED with Spin Qubits file
382 2019-06-04 17:00    Stochastic nature of bacterial eradication using antibiotics file
381 2019-06-12 15:00    The relation between free and interacting fermionic SPT phases file
380 2019-06-17 10:30    Chiral Spintronics file
379 2019-06-24 11:00    Topological photonic anomalies file
378 2019-06-27 14:00    Gapless Kitaev Spin Liquid to Loop and String Gases file
377 2019-06-28 13:30    Magnetic domains and domain wall conduction in pyrochlore iridate thin films and heterostructures file
376 2019-06-28 14:00    1st Research-exchange meeting of computational material physics file
375 2019-07-03 15:00    Many-body quantum electrodynamis (QED) with atoms and photons: A new platform for quantum optics" file