Optical Properties of Multiferroic BiFeO3 Films

Shima, Hiromi; Naganuma, Hiroshi; Okamura, Soichiro

doi:10.5772/54908

Cited by 9 publications

(6 citation statements)

References 40 publications

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“…In these regions, the phonon modes are dominated by either the motion of the oxygen or bismuth ions: 10,28 (b1), (c1), and (d1) show a sketch of the respective ion position within the BFO unit cell. 57 As predicted (refer to the main text), in the three selected wavelength regions, an enhanced near-field response (NF) is observed. Corresponding to the wavelength range of (b2), (c2), and (d2), respectively, (b3), (c3), and (d3) each display three near-field spectra taken at tipsample distances h ¼ 0 nm, 50 nm, and 100 nm.…”

supporting

confidence: 58%

Phonon-induced near-field resonances in multiferroic BiFeO3 thin films at infrared and THz wavelengths

Wehmeier

Nörenberg

Oliveira

et al. 2020

Applied Physics Letters

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Multiferroic BiFeO 3 (BFO) shows several phonon modes at infrared (IR) to THz energies, which are expected to carry information on any sample property coupled to crystal lattice vibrations. While macroscopic IR studies of BFO are often limited by single-crystal size, scatteringtype scanning near-field optical microscopy (s-SNOM) allows for IR thin film spectroscopy of nanoscopic probing volumes with negligible direct substrate contribution to the optical signal. In fact, polaritons such as phonon polaritons of BFO introduce a resonant tip-sample coupling in s-SNOM, leading to both stronger signals and enhanced sensitivity to local material properties. Here, we explore the near-field response of BFO thin films at three consecutive resonances (centered around 5 THz, 13 THz, and 16 THz), by combining s-SNOM with a free-electron laser. We study the dependence of these near-field resonances on both the wavelength and tip-sample distance. Enabled by the broad spectral range of the measurement, we probe phonon modes connected to the predominant motion of either the bismuth or oxygen ions. Therefore, we propose s-SNOM at multiple near-field resonances as a versatile and very sensitive tool for the simultaneous investigation of various sample properties.

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supporting

confidence: 58%

Phonon-induced near-field resonances in multiferroic BiFeO3 thin films at infrared and THz wavelengths

Wehmeier

Nörenberg

Oliveira

et al. 2020

Applied Physics Letters

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“…Secondly, the lattice vibration becomes more intense with increasing temperature. Therefore, in a hightemperature region, the amplitude of the oscillator decreased, and the broadening of the oscillator expanded [10]. The combination of both effects could be responsible for the temperature dependence of the refractive index.…”

Section: Optical Properties Of Mcn Thin Filmsmentioning

confidence: 96%

Temperature dependence of Mn 1.56 Co 0.96 Ni 0.48 O 4 thin films optical properties by spectroscopic ellipsometry

Wang

Zhao

et al. 2014

Materials Letters

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“…Recently, the demand for the use of multiferroics in various fields and products of nanoelectronics has been growing steadily. One of the most interesting compounds in the form of a thin film is bismuth ferrite (BFO) because of its electric [ 1 ], magnetic [ 2 ], piezo [ 3 , 4 ], ferroelectric [ 5 ], dielectric [ 6 ], memristive [ 7 , 8 ] and optical [ 9 , 10 , 11 , 12 ] properties. In addition, BiFeO 3 /reduced graphene oxide composites have excellent photocatalytic characteristics due to improved light absorption, an increase in the number of reactive centers and a low rate of recombination of electron–hole pairs [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Surface Modification and Enhancement of Ferromagnetism in BiFeO3 Nanofilms Deposited on HOPG

et al. 2020

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BiFeO3 (BFO) films on highly oriented pyrolytic graphite (HOPG) substrate were obtained by the atomic layer deposition (ALD) method. The oxidation of HOPG leads to the formation of bubble regions creating defective regions with active centers. Chemisorption occurs at these active sites in ALD. Additionally, carbon interacts with ozone and releases carbon oxides (CO, CO2). Further annealing during the in situ XPS process up to a temperature of 923 K showed a redox reaction and the formation of oxygen vacancies (Vo) in the BFO crystal lattice. Bubble delamination creates flakes of BiFeO3-x/rGO heterostructures. Magnetic measurements (M–H) showed ferromagnetism (FM) at room temperature Ms ~ 120 emu/cm3. The contribution to magnetization is influenced by the factor of charge redistribution on Vo causing the distortion of the lattice as well as by the superstructure formed at the boundary of two phases, which causes strong hybridization due to the superexchange interaction of the BFO film with the FM sublattice of the interface region. The development of a method for obtaining multiferroic structures with high FM values (at room temperature) is promising for magnetically controlled applications.

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Optical Properties of Multiferroic BiFeO3 Films

Cited by 9 publications

References 40 publications

Phonon-induced near-field resonances in multiferroic BiFeO3 thin films at infrared and THz wavelengths

Phonon-induced near-field resonances in multiferroic BiFeO3 thin films at infrared and THz wavelengths

Temperature dependence of Mn 1.56 Co 0.96 Ni 0.48 O 4 thin films optical properties by spectroscopic ellipsometry

Surface Modification and Enhancement of Ferromagnetism in BiFeO3 Nanofilms Deposited on HOPG

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