Interpretation of metallic and semiconducting temperature-dependent resistivity of La1−xNaxMnO3 (x=0.07, 0.13) manganites

Varshney, Dinesh; Choudhary, Dinesh; Shaikh, M. W.

doi:10.1016/j.commatsci.2009.11.012

Cited by 31 publications

(11 citation statements)

References 36 publications

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“…On the other hand, at higher temperatures, the electron conduction is due to the activation above the mobility edge. The above results are consistent with previous work [11,[47][48][49].…”

Section: Discussion and Analysis Of Resultssupporting

confidence: 94%

“…However, the computed values of Debye and Einstein temperatures for La 1-x Na x MnO 3 manganites following the EIoIP approach yield consistent results [47][48][49] with the available experimental results. Furthermore, the optical phonon mode is obtained as x TO & 65.8 (65.7) meV and x LO & 68.8 (68.7) meV for x = 0.05 (0.1), respectively, consistent with the Raman spectroscopy results [4].…”

Section: Discussion and Analysis Of Resultssupporting

confidence: 78%

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Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−x K x MnO3 (x = 0.05, 0.1) manganites

Varshney

Dodiya

2014

J Theor Appl Phys

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The temperature dependence of electrical resistivity, q, of ceramic La 0.7 Ca 0.3-x K x MnO 3 (x = 0.05, 0.1) is investigated in metallic and semi-conducting phase. The metallic resistivity is attributed to be caused by electron-phonon, electron-electron and electron-magnon scattering. Substitutions affect average mass and ionic radii of A-site resulting in an increase in Debye temperature h D attributed to hardening of lattice with K doping. The optical phonon modes shift gradually to lower mode frequencies leading to phonon softening. Estimated resistivity compared with reported metallic resistivity, accordingly q diff. = [q exp. -{q 0 ? q e-ph (=q ac ? q op )}], infers electron-electron and electron-magnon dependence over most of the temperature range. Semi-conducting nature is discussed with variable range hopping and small polaron conduction model. The decrease in activation energies and increase in density of states at the Fermi level with enhanced Ca doping is consistently explained by cationic disorder and Mn valence.

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“…On the other hand, at higher temperatures, the electron conduction is due to the activation above the mobility edge. The above results are consistent with previous work [11,[47][48][49].…”

Section: Discussion and Analysis Of Resultssupporting

confidence: 94%

Section: Discussion and Analysis Of Resultssupporting

confidence: 78%

Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−x K x MnO3 (x = 0.05, 0.1) manganites

Varshney

Dodiya

2014

J Theor Appl Phys

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“…[18] The above values are consistent with the u D values in other monovalent-doped manganites and could not be compared due to the lack of experimental data on silver-doped manganites. [19] It is worth to mention that u D is a function of temperature and varies from technique to technique and its value also varies from sample to sample with an average value and standard deviation of…”

Section: Resultssupporting

confidence: 78%

Thermal conductivity of ferromagnetic metallic La_0.95Ag_0.05MnO₃manganites: role of carrier, spin waves and lattice–impurity scattering

Varshney

Choudhary

Varshney³

et al. 2015

Molecular Simulation

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2015): Thermal conductivity of ferromagnetic metallic La 0.95 Ag 0.05 MnO 3 manganites: role of carrier, spin waves and lattice-impurity scattering, Molecular Simulation,The lattice contribution to the thermal conductivity (k ph ) of La 0.95 Ag 0.05 MnO 3 manganites is theoretically analysed within the framework of Kubo model. The theory is formulated when thermal conduction is limited by the scattering of phonons from defects, grain boundaries, charge carriers, spin waves and phonons. The lattice thermal conductivity dominates in Ag-doped manganites and is artefact of strong phonon -impurity and phonon-phonon scattering mechanism in the ferromagnetic metallic state. The electronic contribution to the thermal conductivity (k e ) is estimated following the Wiedemann-Franz law. Another important contribution in the metallic phase should come from spin waves (k m ). It is noticed that k m increases with a T 2 dependence on the temperature. The behaviour of the thermal conductivity in manganites is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between electron, magnon and phonon contributions.

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“…Their model was found to fit very well the experimental data measured on polycrystalline samples [17,18,34,[39][40][41][42][43], while for epitaxial films, a good fit could be achieved only at low temperatures [35].…”

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confidence: 82%

Polaron framework to account for transport properties in metallic epitaxial manganite films

et al. 2014

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We propose a model for the consistent interpretation of the transport behavior of manganese perovskites in both the metallic and insulating regimes. The concept of polarons as charge carriers in the metallic ferromagnetic phase of manganites also solves the conflict between transport models, which usually neglects polaron effects in the metallic phase, and, on the other hand, optical conductivity, angle-resolved spectroscopy, and neutron scattering measurements, which identify polarons in the metallic phase of manganites down to 6 K. Transport characterizations of epitaxial La 0.7 Sr 0.3 MnO 3 thin films in the thickness range of 5-40 nm and temperature interval of 25-410 K have been accurately collected. We show that taking into account polaron effects allows us to achieve an excellent fit of the transport curves in the whole temperature range. The current carriers density collapse picture accurately accounts for the properties variation across the metal-insulator transitions. The electron-phonon coupling parameter γ estimations are in a good agreement with theoretical predictions. The results promote a clear and straightforward quantitative description of the manganite films involved in charge transport device applications and promises to describe other oxide systems involving a metal-insulator transition. Ferromagnetic manganites are a prototypical example of the so-called half-metallic materials, i.e., materials with 100% spin polarization at 0 K. Although their possible application in commercial spintronics is prevented by a relatively low Curie temperature (T C 370 K), manganites represent an ideal laboratory tool to test spin transport in various materials and to search for pioneering device paradigms [1,2]. Thus, the use of manganites have significantly contributed to the field of organic spintronics, where almost half of the reported devices have La 0.7 Sr 0.3 MnO 3 (LSMO) as an injector [3]. In this context, revealing in a most exhaustive and comprehensive way, the transport properties of these materials looks both captivating and thought provoking.The transport properties of manganites are strongly linked to their ferromagnetism and are generally described in the framework of the so-called double-exchange mechanism: below T C the exchange interaction between Mn cations through oxygen anions favors ferromagnetism and electron delocalization along the Mn-O-Mn bonds, while above T C , thermal disorder disrupts this delocalization leading to a metal-insulator transition (MIT) [4]. Nevertheless, this basic picture appears to be conceptually insufficient to describe the physics of manganites, in general, and LSMO, in particular [5]: the strong role of polaron effects in manganites has been pointed out [6], and good experimental evidence has been provided by a variety of methods [6][7][8][9][10][11][12][13]. Moreover, manganites were proposed as an example of a polaron Fermi liquid [7].Although the presence of polarons in the metallic phase of LSMO (down to 6 K) has been demonstrated by optical * patrizio.gr...

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Interpretation of metallic and semiconducting temperature-dependent resistivity of La1−xNaxMnO3 (x=0.07, 0.13) manganites

Cited by 31 publications

References 36 publications

Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−x K x MnO3 (x = 0.05, 0.1) manganites

Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−x K x MnO3 (x = 0.05, 0.1) manganites

Thermal conductivity of ferromagnetic metallic La_0.95Ag_0.05MnO₃manganites: role of carrier, spin waves and lattice–impurity scattering

Polaron framework to account for transport properties in metallic epitaxial manganite films

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Interpretation of metallic and semiconducting temperature-dependent resistivity of La1−xNaxMnO3 (x=0.07, 0.13) manganites

Cited by 31 publications

References 36 publications

Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−x K x MnO3 (x = 0.05, 0.1) manganites

Metallic and semi-conducting resistivity behaviour of La0.7Ca0.3−x K x MnO3 (x = 0.05, 0.1) manganites

Thermal conductivity of ferromagnetic metallic La0.95Ag0.05MnO3manganites: role of carrier, spin waves and lattice–impurity scattering

Polaron framework to account for transport properties in metallic epitaxial manganite films

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Thermal conductivity of ferromagnetic metallic La_0.95Ag_0.05MnO₃manganites: role of carrier, spin waves and lattice–impurity scattering