Raman scattering study of multiferroic BiFeO3 single crystal

Fukumura, Hiroshi; Harima, Hiroshi; Kisoda, Kenji; Tamada, Minoru; Noguchi, Yuji; Miyayama, Masaru

doi:10.1016/j.jmmm.2006.10.282

Cited by 186 publications

(107 citation statements)

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“…To our knowledge, there are currently no reported experimental data of the full magnon and phonon spectra in BFO, however. Multiple Raman measurements have been performed, but these only probe modes at small wavevectors q → 0 [10][11][12][13][14][15][16][17][18][19][20] . Here, we report the first INS measurement of the phonon DOS in polycrystalline BiFeO 3 , as a function of T , as well as more detailed measurements of the magnon spectrum than previously reported 21 .…”

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confidence: 99%

Anharmonic phonons and magnons in BiFeO3

Delaire

Stone

et al. 2012

Phys. Rev. B

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The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO3 were measured for temperatures 200 ≤ T ≤ 750 K , using inelastic neutron scattering (INS). Our results indicate that the magnetic spectrum of BiFeO3 closely resembles that of similar Fe perovskites, such as LaFeO3, despite the cycloid modulation in BiFeO3. We do not find any evidence for a spin gap. A strong T -dependence of the phonon DOS was found, with a marked broadening of the whole spectrum, providing evidence of strong anharmonicity. This anharmonicity is corroborated by large-amplitude motions of Bi and O ions observed with neutron diffraction. A clear anomaly is seen in the T dependence of Bi-dominated modes across the Néel transition. These results highlight the importance of spin-phonon coupling in this material.

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Section: Introductionmentioning

confidence: 99%

Anharmonic phonons and magnons in BiFeO3

Delaire

Stone

et al. 2012

Phys. Rev. B

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“…The E(1) mode softens strongly from 5 K to room temperature. High temperature infrared [16] and Raman [12,13] measurements indicate that this mode continues to soften but instead of smoothly decreasing to zero frequency it drops rather abruptly at the transition. Modes E(2), E(6) and E(8) show the same behavior as mode E(1).…”

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confidence: 97%

“…Optical spectroscopy is a very powerful tool to understand the driving mechanism of the ferroelectric transition and, eventually, its coupling to magnetic ordering [10,11]. Nevertheless, only a few Raman [12,13,14] and infrared (IR) [15,16] studies on BiFeO 3 are known to date. Surprisingly none of the IR measurements were carried out on single crystals.…”

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confidence: 99%

“…Nevertheless, only a few Raman [12,13,14] and infrared (IR) [15,16] studies on BiFeO 3 are known to date. Surprisingly none of the IR measurements were carried out on single crystals.…”

mentioning

confidence: 99%

“…Although these results found the proper number of modes, they cannot clarify the symmetry of the phonons. Some extra insight on the phonon assignment was obtained on more recent Raman data [13,14] but some inconsistencies in phonon assignment remain. In addition, Haumont et al [12] argued that because the frequency of the lowest mode did not vanish smoothly at the Curie temperature, the ferroelectric transition in BiFeO 3 would not be soft-mode driven.…”

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Infrared phonon dynamics of a multiferroicBiFeO3single crystal

et al. 2007

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We discuss the first infrared reflectivity measurement on a BiFeO3 single crystal between 5 K and room temperature. The 9 predicted ab-plane E phonon modes are fully and unambiguously determined. The frequencies of the 4 A1 c-axis phonons are found. These results settle issues between theory and data on ceramics. Our findings show that the softening of the lowest frequency E mode is responsible for the temperature dependence of the dielectric constant, indicating that the ferroelectric transition in BiFeO3 is soft-mode driven.PACS numbers: 78.30.-j, 77.84.-s, 77.22.-d The interplay between magnetic and dielectric properties is an intriguing subject that was already discussed by Pierre Curie in 1894 [1]. Such, magnetoelectric effects were subject of extensive studies during the 1960s [2,3,4]. More recently, the ability of controlling the dielectric properties through a magnetic field and viceversa renewed the interest in these materials [6,7,8]. Coupling between electrical and magnetic properties are particularly interesting in multiferroic materials, which present simultaneously two or more ferroic or antiferroic order parameters. Optical spectroscopy is a very powerful tool to understand the driving mechanism of the ferroelectric transition and, eventually, its coupling to magnetic ordering [10,11]. Nevertheless, only a few Raman [12,13,14] and infrared (IR) [15,16] studies on BiFeO 3 are known to date. Surprisingly none of the IR measurements were carried out on single crystals. There are two important open questions concerning the electrodynamics of BiFeO 3 : (i) the phonon modes symmetry; and (ii) the role (or absence of thereof) of phonon softening in the ferroelectric transition.In its ferroelectric phase, BiFeO 3 belongs to the R3c (C 6 3v ) space group, which derives from the ideal (paraelectric) P m3m (O 1 h ) cubic perovskite group by a small distortion along the (111) cubic directions. Its magnetic structure is a spiral-cycloidal incommensurate phase. Group theory analysis for the R3c ferroelectric group predicts 4A 1 ⊕ 5A 2 ⊕ 9E optical phonon modes [16]. The A 1 modes are infrared active along the c-axis, the E modes are infrared active on the ab-plane and the A 2 modes are silent. Early Raman data [12] found at least 11 modes at room temperature. Kamba et al. [16] proposed to fit the infrared data on ceramics using 13 Lorentz oscillators. Although these results found the proper number of modes, they cannot clarify the symmetry of the phonons. Some extra insight on the phonon assignment was obtained on more recent Raman data [13,14] but some inconsistencies in phonon assignment remain. In addition, Haumont et al. [12] argued that because the frequency of the lowest mode did not vanish smoothly at the Curie temperature, the ferroelectric transition in BiFeO 3 would not be soft-mode driven. This picture was later revised to propose that the incomplete phonon softening could rather be a sign of a first order transition [16,20]. However, both scenarios remain speculative.In this paper, we show the p...

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Temperature‐dependent Raman scattering studies of polycrystalline BiFeO₃ bulk ceramics

Rout

Moon

Kang

2009

J Raman Spectroscopy

110

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This work reports the temperature-dependent Raman scattering study of mutiferroic BiFeO 3 (BFO) bulk ceramics in a wide temperature range of 93-843 K. The polycrystalline samples are sintered at four different temperatures and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry, differential scanning calorimetry (DSC), and optical microscopy. The microstructure shows remarkable changes in terms of grain size and domain pattern as the sintering temperature increases. The DSC curves show prominent exothermic peaks at 645 K, the antiferromagnetic-paramagnetic phase transition temperature. The Raman spectra of all the four specimens reveal strong anomalies in the vicinity of the Neel temperature, which can be attributed to the multiferroic nature of BFO. The Raman scattering studies also reveal considerable spectral changes at a temperature range of 140-200 K in all the specimens, which can be inferred to a further spin-reorientation transition exhibited in BFO at a cryogenic temperature.

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Raman scattering study of multiferroic BiFeO3 single crystal

Cited by 186 publications

References 6 publications

Anharmonic phonons and magnons in BiFeO3

Anharmonic phonons and magnons in BiFeO3

Infrared phonon dynamics of a multiferroicBiFeO3single crystal

Temperature‐dependent Raman scattering studies of polycrystalline BiFeO₃ bulk ceramics

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Raman scattering study of multiferroic BiFeO3 single crystal

Cited by 186 publications

References 6 publications

Anharmonic phonons and magnons in BiFeO3

Anharmonic phonons and magnons in BiFeO3

Infrared phonon dynamics of a multiferroicBiFeO3single crystal

Temperature‐dependent Raman scattering studies of polycrystalline BiFeO3 bulk ceramics

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Temperature‐dependent Raman scattering studies of polycrystalline BiFeO₃ bulk ceramics