Evidence for magnetic correlation in the paramagnetic phase of DyMn 2 O 5

Advances in Materials Science and Engineering

Mansoor

Rehmani

et al. 2017

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We present infrared (IR) reflectivity of Gd1-xYxMn2O5 with x = 0, 0.2, 0.4, 0.6, 0.8, and 1 in the frequency range 30–1000 cm−1. A total of 18 IR active phonons were observed for GdMn2O5 (x=0) and three additional phonons have been observed with increasing x, marking a total of 21 phonons in YMn2O5 (x=1). A systematic investigation was performed to map out the structural distortion through the lattice vibration and discuss the consequences of frequency shifts in phonon modes. In addition, we have calculated the real part of optical conductivity (σ1(ω)) which reflects the semiconducting nature of Gd1-xYxMn2O5.

Section: Introductionsupporting

confidence: 71%

“…Gd 1− Y Mn 2 O 5 ceramic samples have been synthesized by using sol-gel method, similar to other Mn 2 O 5 compounds [10,11,21]. Fourier transform infrared (FTIR) spectrometer (Vertex 80v) has been used to measure the IR reflectivity.…”

Section: Methodsmentioning

confidence: 99%

Lattice Dynamics of Gd_1−xY_xMn₂O₅ Investigated by Infrared Spectroscopy

Advances in Materials Science and Engineering

Mansoor

Rehmani

et al. 2017

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“…Remarkably, recently we have observed an unconventional magnetodielectric effect in DyMn 2 O 5 above , where the infrared and Raman phonons have shown spin-phonon coupling and confirm the strong correlation between spin, charge, and lattice degree of freedom [8]. Such a strong interplay between many degrees of freedom in the paramagnetic phase is a special characteristic of Mn 2 O 5 family [5][6][7][8][9]. The knowledge of lattice vibrations and their correlation to different conduction mechanisms is of crucial importance for engineering the materials for various technological applications.…”

Section: Introductionsupporting

confidence: 60%

“…Moreover, spin-phonon coupling has been observed slightly above indicating the drastic change in phonon frequency due to magnetic field and temperature [6,7]. Remarkably, recently we have observed an unconventional magnetodielectric effect in DyMn 2 O 5 above , where the infrared and Raman phonons have shown spin-phonon coupling and confirm the strong correlation between spin, charge, and lattice degree of freedom [8]. Such a strong interplay between many degrees of freedom in the paramagnetic phase is a special characteristic of Mn 2 O 5 family [5][6][7][8][9].…”

Section: Introductionsupporting

confidence: 60%

Lattice Dynamics and Transport Properties of Multiferroic DyMn₂O₅

Advances in Condensed Matter Physics

Bukhari

Jamil

et al. 2017

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We have investigated the optical and electrical properties of polycrystalline DyMn2O5synthesized by sol-gel method. Analysis of the reflectivity spectrum has led to the observation of 18 infrared (IR) active phonon modes out of 36 predicted ones. We discuss the results in terms of different phonon bands originated as a result of atomic vibrations. Moreover, the optical energy band gap ofEg(OC)~1.78 eV has been estimated from optical conductivity(σ1(ω))spectrum. The energy band gap and optical transitions were also determined from UV-visible absorption spectrum and band gap ofEg(UV)~1.57 eV was estimated. Moreover, DC electrical resistivity shows the p-type polaronic conduction above room temperature.

“…[18] Very recently, we observed an anomalous behavior in the dielectric constant slightly above the Néel temperature in GdMn 2 O 5 [20] and DyMn 2 O 5 . [21] In this regard, we are motivated to conduct temperature dependent dielectric measurements in the paramagnetic phase of NdMn 2 O 5 to reveal the existence of a dielectric response at high temperature in this compound. As Nd 3+ has a larger ionic size as compared to Gd 3+ and Dy 3+ , so we expect some interesting results that can shed light on the role of the R 3+ ion in the family of RMn 2 O 5 .…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectric effect in multiferroic NdMn ₂ O ₅

Bukhari

2017

Chinese Phys. B

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We have measured the dielectric constant for NdMn 2 O 5 in an external magnetic field to map out the magnetoelectric phase diagram. The phase diagram corresponds well with the previously reported data of neutron diffraction and magnetic susceptibility. Our main finding is the observation of a dielectric anomaly in the low temperature phase with a strong magnetoelectric effect, which is attributed to the independent Nd 3+ ordering. Moreover, the absence of the dielectric anomaly in the paramagnetic phase is discussed, keeping in view the exchange interaction and its dependence on the rareearth R 3+ ionic radius.