Lattice Dynamics of Gd1−xYxMn2O5 Investigated by Infrared Spectroscopy

Ahmad, Javed; Mansoor, Jawaria; Rehmani, Mehr Khalid; Jamil, Muhammad; Bukhari, Syed Hamad

doi:10.1155/2017/3040254

Cited by 3 publications

(5 citation statements)

References 28 publications

(34 reference statements)

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“…Here, we have estimated the indirect energy band gap of about E g ∼ 1.5 eV by extrapolating the linear part of spectrum to the x-axis which is calibrates as energy axis as shown in figure 5. The estimated value of E g is close to the band gap observed for related compounds such as TbMn 2 O 5 ∼ 1.70 eV, YMn 2 O 5 ∼ 1.61 eV, DyMn 2 O 5 ∼ 1.45 eV [12,25].…”

Section: Uv-visible Spectroscopysupporting

confidence: 83%

“…Remarkably, an electric polarization has been observed at room temperature for GdMn 2 O 5 [11]. We have also reported the vibrational phonon dynamics for GdMn 2 O 5 , DyMn 2 O 5 , and YMn 2 O 5 and find that they exhibits orthorhombic structure and have shown strong structural distortion due to the change in ionic radius of + R 3 [12,13]. A key issue is thus to understand the effect of + R 3 on physical properties, more generally, optical and transport properties of the system at room temperature and above.…”

Section: Introductionmentioning

confidence: 64%

“…The observed phonon modes for SmMn [12,13]. This also reflects that R-site induces large structural distortion in the system.…”

Section: Optical Phononsmentioning

confidence: 97%

See 2 more Smart Citations

Optical and dielectric spectroscopic analysis of SmMn₂O₅

Ahmad¹,

Bukhari²,

Khan³

et al. 2020

Phys. Scr.

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Polycrystalline SmMn2O5 has been synthesized by using sol-gel auto combustion tecnique. X-ray diffraction (XRD) pattern reflects the single phase formation of orthorhombic structure with Pbam space group. In the frequency range of (30–1000 cm−1) reflectivity spectrum reveals the 14 infrared active phonons out of 36, which are already pridicted theoretically. We have estimated the optical energy band gap (E g ) ≃ 1.5 eV from UV–visible absorption spectrum. Temperature dependent (293-533 K) DC electrical characterization up to 40 V suggests semiconducting nature of the material. The temperature dependent impedance spectroscopy within a broader frequency range of (20 Hz—3 GHz) shows decreasing behavior of dielectric constant and tangent loss while AC conductivity increasing with the rise in frequency and temperature suggest the strong frequency dispersion and relaxational behavior of the material. The activation energy calculation from AC conductivity is in good agreement with semiconducting material energy band gap.

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Section: Uv-visible Spectroscopysupporting

confidence: 83%

Section: Introductionmentioning

confidence: 64%

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Optical and dielectric spectroscopic analysis of SmMn₂O₅

Ahmad¹,

Bukhari²,

Khan³

et al. 2020

Phys. Scr.

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“…According to lattice dynamics calculations, RMn 2 O 5 compounds exhibit 36 IR active modes at the Γ-point depending on the crystal direction (8B 1u (E||z)+14B 2u (E||y)+14B 3u (E||x)) [18]. However, of those 36 phonon modes, only 13 modes are observed in HMO and are in good agreement with other polycrystalline RMn 2 O 5 (R = Sm, Nd, Gd, Dy, and Y) compounds [19][20][21]. The cause of this difference lies in the polycrystalline nature of our compound having mixed ab-plane and c-axis response.…”

Section: Infrared Reflectivitysupporting

confidence: 62%

Structural and spectroscopic analysis of HoMn₂O₅ multiferroics

Ahmad

Afzal²,

Nissar³

et al. 2022

Phys. Scr.

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HoMn2O5was synthesized by sol-gel auto combustion method and analyzed through x-ray diffraction, Fourier transform infrared reflectivity, Raman, UV-visible, Photoluminescence spectroscopies at room temperature and transport properties (applying dc- and ac- electric field) at high temperatures. Structural characterizations revealed single-phase nature and the analysis confirms the crystal structure by Rietveld refinement with orthorhombic symmetry (space group Pbnm). Both Scherer formula and Williamson-Hall analysis have been used to estimate the average grain size; the results come in good agreement. The reflectivity spectrum was fitted by the Lorentz oscillator model to account for the infrared active optical phonons. The Raman spectrum was measured in unpolarized geometry using a 514 nm laser excitation source, which confirmed its orthorhombic crystal structure. UV-visible spectroscopy demonstrated the electronic structure and semiconducting behavior of sample with an estimated bandgap of 1.54 eV. PL spectrum suggested its electronic transition and vibrations of Mn-O bonds. The conduction mechanism was investigated by measuring electrical resistivity in temperature range (293-473K) by two probe method. Dielectric properties have been discussed in terms of variation in dielectric constant, tangent loss, and conductivity as a function of temperature and frequency.

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“…Structural characterization.-Figure 1a shows the X-ray diffraction patterns of Ho doped GdMn 2 O 5 . The XRD pattern is compared with the literature 18,20 and it is found that the structure is orthorhombic. It is also observed that the peaks shift towards the higher angles as Ho 3+ concentration increases.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Room Temperature Structural, Optical, Electrical Properties of Holmium Doped GdMn₂O₅ Multiferroics

N¹,

Dasari²,

Kishore

et al. 2023

ECS J. Solid State Sci. Technol.

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Multiferroic materials with the compositional formulae Gd1-xHoxMn2O5 (x = 0, 0.1, 0.2, 0.3, and 0.4) were prepared by the conventional solid-state reaction method. The structural analysis has been carried out by X-ray diffraction technique which confirms the orthorhombic structure with the Pbam space group. The optical properties have been studied by UV Visible, FTIR, and Raman spectra. The energy gap that was calculated using UV visible absorption spectra shows that the material is semiconducting in nature. The observed 14 Raman and 17 IR active modes are attributed to the relative motions of corresponding atoms. ; also by increasing the doping concentration of Ho, the emergence of phonon shifting was observed which suggests the possible multiferroic coupling behaviour. The electrical properties including dielectric constant, dielectric loss, and ac conductivity at room temperature indicate the spin-lattice coupling.

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Lattice Dynamics of Gd_1−xY_xMn₂O₅ Investigated by Infrared Spectroscopy

Cited by 3 publications

References 28 publications

Optical and dielectric spectroscopic analysis of SmMn₂O₅

Optical and dielectric spectroscopic analysis of SmMn₂O₅

Structural and spectroscopic analysis of HoMn₂O₅ multiferroics

Synthesis and Room Temperature Structural, Optical, Electrical Properties of Holmium Doped GdMn₂O₅ Multiferroics

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Lattice Dynamics of Gd1−xYxMn2O5 Investigated by Infrared Spectroscopy

Cited by 3 publications

References 28 publications

Optical and dielectric spectroscopic analysis of SmMn2O5

Optical and dielectric spectroscopic analysis of SmMn2O5

Structural and spectroscopic analysis of HoMn2O5 multiferroics

Synthesis and Room Temperature Structural, Optical, Electrical Properties of Holmium Doped GdMn2O5 Multiferroics

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Product

Resources

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Lattice Dynamics of Gd_1−xY_xMn₂O₅ Investigated by Infrared Spectroscopy

Optical and dielectric spectroscopic analysis of SmMn₂O₅

Optical and dielectric spectroscopic analysis of SmMn₂O₅

Structural and spectroscopic analysis of HoMn₂O₅ multiferroics

Synthesis and Room Temperature Structural, Optical, Electrical Properties of Holmium Doped GdMn₂O₅ Multiferroics