Polaron Hopping Induced Giant Room‐Temperature Magnetodielectric Effect in Disordered Rutile NiNb 2 O 6

The crystal structure at room temperature (RT), thermal expansion from RT to 1000°C and electrical conductivity, from RT to 600°C, of the perovskite-type oxides in the system Pr 1-x Sr x FeO 3(x = 0, 0.2, 0.4, 0.6) were studied. All the compounds have the orthorhombic perovskite GdFeO 3-type structure with space group Pbnm. The lattice parameters were determined by X-ray powder diffraction. The Pseudo cubic lattice parameter decreases with an increase in x, while the coefficient of linear thermal expansion increases. The thermal expansion is almost linear for x = 0 and 0.2. The electrical conductivity increases with increasing x while the activation energy decreases. The electrical conductivity can be described by the small polaron hopping conductivity model.

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Room temperature weak multiferroism and magnetodielectric effect in highly oriented (Y0.9Bi0.1)(Fe0.5Cr0.5)O3 thin films

Materials Research Bulletin ◽

10.1016/j.materresbull.2015.03.040 ◽

2015 ◽

Vol 68 ◽

pp. 49-53 ◽

Cited By ~ 5

Author(s):

Yogesh Sharma ◽

Pankaj Misra ◽

Danilo G. Barrionuevo Diestra ◽

Ratnamala Chatterjee ◽

Ram S. Katiyar

Keyword(s):

Thin Films ◽

Room Temperature ◽

Magnetodielectric Effect

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Room temperature magnetodielectric effect in composites of cobalt containing silica based nanoglass and mesoporous alumina

10.1063/5.0016735 ◽

2020 ◽

Author(s):

Anupam Maity ◽

Subha Samanta ◽

Debasish Biswas ◽

Dipankar Chakravorty

Keyword(s):

Room Temperature ◽

Mesoporous Alumina ◽

Magnetodielectric Effect

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Large magnetodielectric effect and negative magnetoresistance in NiO nanoparticles at room temperature

RSC Advances ◽

10.1039/d0ra00188k ◽

2020 ◽

Vol 10 (23) ◽

pp. 13708-13716 ◽

Cited By ~ 1

Author(s):

Soumi Chatterjee ◽

Ramaprasad Maiti ◽

Dipankar Chakravorty

Keyword(s):

Polarization Effect ◽

Room Temperature ◽

Negative Magnetoresistance ◽

Nio Nanoparticles ◽

Chemical Route ◽

Simple Chemical ◽

Magnetodielectric Effect

This work presents NiO nanoparticles synthesized by simple chemical route showing large magnetodielectric effect at room temperature resulted from Maxwell–Wagner polarization effect which was arising due to large negative magnetoresistance.

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Effective Way to Improve the Magnetoresistance Effect in Perovskite at Room Temperature

Materials Science Forum ◽

10.4028/www.scientific.net/msf.704-705.954 ◽

2011 ◽

Vol 704-705 ◽

pp. 954-959

Author(s):

Bao Xin Huang ◽

Jian Li ◽

Jun Hua Wang ◽

Ke Zheng Chen ◽

Yi Hua Liu ◽

...

Keyword(s):

Room Temperature ◽

Composite System ◽

Small Polaron ◽

Application Research ◽

Polaron Hopping ◽

Conduction Electrons ◽

Effective Selection ◽

Spin Dependent Scattering ◽

Mr Effect ◽

Hopping Model

The magnetic and electrical properties of the La0.67Ca0.25Sr0.08MnO3/xAg composite system are systematically investigated as a function of Ag-added content. With increasing the Ag dopant amount, the magnetization decreases a little while Curie temperature (TC) is almost independent of Ag content around 312 K. The resistivity reduces rapidly with Ag addition ( x < 0.25 ) due to the decomposed metal Ag, and then it increases slightly which is probably induced by the less Ag content related to the volatilization of Ag during calcinations. At low temperature, the ρ – T curves ﬁt well by the expression of ρ =ρ0 +ρ2T2 +ρ4.5T4.5 while all data for the above TC can be ﬁtted by using the adiabatic small-polaron-hopping model ρ=ρ0T exp (E/kBT ). The enhancement of MR effect ( 41% ) at room temperature is mainly related to the coexistence of intrinsic MR properties and the spin dependent scattering of conduction electrons at the interfaces. These results indicate that combining the doping effect with the composite method is an effective selection in enhancement of MR at room temperature, which is very meaningful for the application research.

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Conduction in LaCoO3by small-polaron hopping below room temperature

Physical Review B ◽

10.1103/physrevb.54.17431 ◽

1996 ◽

Vol 54 (24) ◽

pp. 17431-17437 ◽

Cited By ~ 116

Author(s):

E. Iguchi ◽

K. Ueda ◽

W. H. Jung

Keyword(s):

Room Temperature ◽

Small Polaron ◽

Polaron Hopping ◽

Small Polaron Hopping

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Nickel Manganite-Sodium Alginate Nano-Biocomposite for Temperature Sensing

Chemosensors ◽

10.3390/chemosensors9090241 ◽

2021 ◽

Vol 9 (9) ◽

pp. 241

Author(s):

Milena P. Dojcinovic ◽

Zorka Z. Vasiljevic ◽

Janez Kovac ◽

Nenad B. Tadic ◽

Maria Vesna Nikolic

Keyword(s):

Activation Energy ◽

Sodium Alginate ◽

Room Temperature ◽

Small Polaron ◽

Spinel Phase ◽

Sol Gel ◽

Complex Impedance ◽

Relaxation Frequency ◽

Polaron Hopping ◽

Ft Ir

Nanocrystalline nickel manganite (NiMn2O4) powder with a pure cubic spinel phase structure was synthesized via sol-gel combustion and characterized with XRD, FT-IR, XPS and SEM. The powder was mixed with sodium alginate gel to form a nano-biocomposite gel, dried at room temperature to form a thick film and characterized with FT-IR and SEM. DC resistance and AC impedance of sensor test structures obtained by drop casting the nano-biocomposite gel onto test interdigitated PdAg electrodes on an alumina substrate were measured in the temperature range of 20–50 °C at a constant relative humidity (RH) of 50% and at room temperature (25 °C) in the RH range of 40–90%. The material constant obtained from the measured decrease in resistance with temperature was determined to be 4523 K, while the temperature sensitivity at room temperature (25 °C) was −5.09%/K. Analysis of the complex impedance plots showed a dominant influence of grains. The decrease in complex impedance with increase in temperature confirmed the negative temperature coefficient effect. The grain resistance and grain relaxation frequency were determined using an equivalent circuit. The activation energy for conduction was determined as 0.45 eV from the temperature dependence of the grain resistance according to the small polaron hopping model, while the activation energy for relaxation was 0.43 eV determined from the Arrhenius dependence of the grain relaxation frequency on temperature.

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Dielectric relaxation and current conduction mechanism of Tb and Mn codoped bismuth ferrite grafted poly (vinyl alcohol) nanocomposite film

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2020-0040 ◽

2020 ◽

Vol 59 (1) ◽

pp. 425-433

Author(s):

Monalisa Halder ◽

Ajit Kumar Meikap

Keyword(s):

Nanocomposite Film ◽

Room Temperature ◽

Conduction Mechanism ◽

Electric Modulus ◽

Complex Modulus ◽

Bismuth Ferrite ◽

Poly Vinyl Alcohol ◽

Polaron Hopping ◽

Current Conduction ◽

Hopping Model

AbstractInvestigation on current conduction mechanism through Tb and Mn codoped Bismuth Ferrite grafted polyvinyl alcohol (BTFMO-PVA) nanocomposite film above room temperature (300 K – 415 K) is reported here in detail. A detailed study on dielectric properties of the sample is done over a wide temperature range in a frequency range of 20 Hz - 2MHz. The conduction is attributed to correlated barrier hopping model. Bipolaron hopping dominates over single-polaron hopping in this system. Complex electric modulus spectra and complex modulus spectra are well explained by suitable models to understand the effective dielectric response. The sample responds to the externally applied magnetic field exhibiting negative magnetocapacitance at room temperature.

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