Non-adiabatic small-polaron hopping conduction in Pr0.65Ca0.35−xSrxMnO3 perovskites above the metal–insulator transition temperature

Mollah, S.; Huang, Hsuan‐Jung; Yang, H. D.; Pal, Sarmistha; Taran, Subhrangsu; Chaudhuri, B. K.

doi:10.1016/j.jmmm.2004.07.004

Cited by 57 publications

(19 citation statements)

References 42 publications

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“…At the zero gate, the Debye temperatures θ D were obtained as ß260 and ß272 K for the cooling and the warming cycles, respectively. These values are much lower than the Debye temperatures reported for polycrystalline PCSMO samples [77] but comparable to the value determined for Pr 0.5 Ca 0.5 MnO 3 films [80].…”

Section: B Electric Field Effect On the Small Polaron Transportsupporting

confidence: 79%

“…3(a), the small polaron model is in good agreement with the transport data in the high-temperature range, i.e., T > θ D /2, with θ D being the Debye temperature, while notable deviation emerges at lower temperatures due to band conduction and quantum contributions [80]. The value of θ D can be estimated as the temperature at which linearity of ln(σ T ) vs 1/T disappears in the high-temperature region [77]. At the zero gate, the Debye temperatures θ D were obtained as ß260 and ß272 K for the cooling and the warming cycles, respectively.…”

Section: B Electric Field Effect On the Small Polaron Transportsupporting

confidence: 74%

“…At temperatures above the T P , the transport in hole-doped manganites is generally of the polaron hopping type as a result of the strong electron-lattice interaction [77]. Depending on the preparation method and the crystalline nature of the manganite films, the polaron hopping transport follows three models; i.e., (i) thermally activated hopping, (ii) variable range hopping, and (iii) small polaron hopping [78].…”

Section: B Electric Field Effect On the Small Polaron Transportmentioning

confidence: 99%

“…This indicates that the dynamic oxygen migration at the channel-ionic liquid interface may not be the dominant mechanism underlying the observed transport modulation, although further confirmation is needed in future experiments. It is known that the Pr 0.65 (Ca y Sr 1−y ) 0.35 MnO 3 series of compounds display a strong electron-phonon interaction characterized by a large polaron coupling constant (γ p > 4) and a giant ratio of polaron mass (m p ) to lattice effective mass (m * ) [77]. This strong electron-phonon coupling in the PCSMO channel is likely the reason behind the observed negligible ER in the small polaron transport regime.…”

Section: B Electric Field Effect On the Small Polaron Transportmentioning

confidence: 99%

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Electric field tuning of phase separation in manganite thin films

Lourembam

Ding

et al. 2014

Phys. Rev. B

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In this paper, we investigate the electric field effect on epitaxial Pr 0.65 (Ca 0.75 Sr 0.25 ) 0.35 MnO 3 thin films in electric double-layer transistors. Different from the conventional transistors with semiconducting channels, the sub(micrometer)-scale phase separation in the manganite channels is expected to result in inhomogeneous distribution of mobile carriers and local enhancement of electric field. The field effect is much larger in the low-temperature phase separation region compared to that in the high-temperature polaron transport region. Further enhancement of electroresistance is achieved by applying a magnetic field, and a 250% modulation of resistance is observed at 80 K, equivalent to an increase of the ferromagnetic metallic phase fraction by 0.51%, as estimated by the general effective medium model. Our results illustrate the complementary nature of electric and magnetic field effects in phase-separated manganites, providing insights on such novel electronic devices based on complex oxides.

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Section: B Electric Field Effect On the Small Polaron Transportsupporting

confidence: 79%

Section: B Electric Field Effect On the Small Polaron Transportsupporting

confidence: 74%

Section: B Electric Field Effect On the Small Polaron Transportmentioning

confidence: 99%

Section: B Electric Field Effect On the Small Polaron Transportmentioning

confidence: 99%

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Electric field tuning of phase separation in manganite thin films

Lourembam

Ding

et al. 2014

Phys. Rev. B

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“…For LBMO/NiO, SPH and VRH are present together in the as prepared and annealed samples, and the θ D and ph v values are fluctuating with annealing temperatures (see Table 2). E ρ , decreases with the annealing temperatures in both LBMO and LBMO/NiO, [22].…”

Section: Conduction Mechanismmentioning

confidence: 95%

The annealing influence onto the electrical and magnetic behavior of magnetoresistive/insulator system

Ahmed

Mohamed

et al. 2016

Low Temperature Physics

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This investigation is mainly concerned with the effect of annealing temperature (600, 700, 800 and 900 °C) in air for (La 0.7 Ba 0.3 MnO 3 ) 1-x /(NiO) x with x = 0 and x = 0.10 samples. It was shown that the annealing temperature does not affect the structure and parameters of rhombohedral lattice of the samples. However, it is observed that the annealing treatment has a notable effect on the electrical resistivity and the metal-semiconductor transition temperature T ms . Temperature dependent magnetization measurements showed a decrease in Curie temperature T C with annealing temperature. In the same time, annealing process decreases the magnetoresistance of La 0.7 Ba 0.3 MnO 3 , in contrast to (La 0.7 The magnetoresistive material was mixed with an insulator material to enhance the extrinsic CMR that depending on grain boundaries [6] and spin tunneling [7], that CMR may increase under low magnetic fields known as low field magnetoresistance (LFMR). The importance of LFMR refers to use low magnetic field to get high values of MR what is making it useful for applications. This LFMR can be affected by other several factors; one of them is annealing temperature that can affect the grain size and hence the physical properties including LFMR. An annealing effect has a little attention in this direction, especially in LBMO/insulator. Therefore in this work the effects of annealing temperature on the electrical, magnetic, magnetoresistance and thermoelectric properties of La 0.7 Ba 0.3 MnO 3 (LBMO) and (La 0.7 Ba 0.3 MnO 3 ) 0.9 /(NiO) 0.1 (LBMO/NiO) are examined. Experimental(La 0.7 Ba 0.3 MnO 3 ) 1-x /(NiO) x ceramic samples were prepared by the conventional solid state reaction method (x = = 0.0 & 0.10). La 2 O 3 , BaCO 3 and MnCO 3 raw materials were mixed in stoichiometric proportions, ground, pelletized and calcined at 900 °C for 24 h. It was reground again and pelletized and then sintered at 1100 °C for 24 h. NiO insulator was added in stoichiometric portions to the sintered La 0.7 Ba 0.3 MnO 3 compound and lightly ground, then pressed and put in 1000 °C for 24 h. The composites of LBMO and LBMO/NiO annealed for 2 h at 600, 700, 800 and 900 °C. Electrical resistivity was measured by van der Pauw technique in the presence and absence of 0.6 T magnetic field. Samples were examined by x ray, using Brucker (Axs-D& Advance) powder diffractometer at room temperature with Cu (K α ) radiation (λ = 1.5406 Å). The microstructure was investigated by Jeol JSM-6610LV

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Evaluation of Polaron Transport in Solids from First‐principles

Natanzon

Azulay

Amouyal

2020

Israel Journal of Chemistry

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Polarons are formed in polar or ionic solids, either molecular or crystalline, due to local distortions of the lattice induced by charge carriers. Polaron hopping is the primary mechanism of charge transport in these materials, such as functional ceramic compounds, with applications in photovoltaics, thermoelectrics, two-dimensional electron gas transistors, magnetic sensors, spin valve devices, and memories. Understanding the fundamental physics of polaron hopping is, therefore, of prime technological importance. This article provides a brief physical background of polarons and their hopping mechanism, focusing on first-principles calculations of polaron properties. Herein, we review recent selected studies applying the density functional theory (DFT), and describe the merits and challenges in applying DFT for such calculations, highlighting the need to address both electronic and vibrational aspects. The vibrational component of the polaron is evaluated based on structural and total energy calculations, whereas the electronic component is derived from both total energy and electron density calculations. To address the most compelling challenge of calculating polaron properties using DFT, which is the issue of electron localization, we propose to employ calculations of selected vibrational properties, such as the sound velocity, shear modulus, and Grüneisen parameter, to represent the polaron hopping energy; all of which originate from the stiffness of inter-atomic bonds. Such methodology is expected to be more straightforward than the existing ones, however demands standardization. Keywords: charge transport • polaron hopping • first-principles calculations • oxides • vibrational properties nism dominating the transport correlates to the Debye temperature, θ D. At low temperatures, where T < θ D /2, tunneling predominates, whereas at higher temperatures hopping is more probable. Reports on TMOs are available for many systems, such as CaMnO 3 , [4-10] (

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Non-adiabatic small-polaron hopping conduction in Pr0.65Ca0.35−xSrxMnO3 perovskites above the metal–insulator transition temperature

Cited by 57 publications

References 42 publications

Electric field tuning of phase separation in manganite thin films

Electric field tuning of phase separation in manganite thin films

The annealing influence onto the electrical and magnetic behavior of magnetoresistive/insulator system

Evaluation of Polaron Transport in Solids from First‐principles

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