Adiabatic Small Polaron Hopping Research Articles

Rietveld refined structural, optical and temperature dependent impedance spectroscopy of NiO–ZnO heterostructure composite: Synthesized through solid state method for high-frequency devices

Multifunctional NiO–ZnO heterostructure composite powder is economically synthesized through a solid-state route having a crystallite size of 23 (±2) nm. Chemical composition is identified through FTIR, the peak associated with Zn–O is detected at 1049 cm−1. However, the peaks detected at 870 cm−1 and 590 cm−1 show Ni–O stretching vibrations. UV-DRS technique is employed to estimate the energy band gap (Eg) around 3.18 eV. The impedance studies confirmed the presence of a non-Debye-type relaxation mechanism, electrical parameters confirm the contribution of electroactive regions i.e. grains and interfaces. An equivalent circuit model (R-CPE) is employed to measure various electrical parameters. Adiabatic small polaron hopping model is applied to estimate activation energies for Ni+2 (0.30 eV), Zn+2 (0.35 eV), and bulk (0.32 eV) respectively. The hopping length at the interface is estimated at around 0.8 Å by employing Mott's variable range hopping model. Jonscher's power law (JPL) is used to fit ac conductivity data, and conclude activation energy around 0.3 eV. The conduction mechanism through the whole frequency range (1–107 Hz) is governed by correlated barrier hopping. Various physical parameters i.e. binding energy (Wm), hopping length, and barrier height compared throughout the whole temperature range (313–393 K). The rate of increase in real permittivity at low frequency is related to the disorder of the cation at sublattices. These results deduced potential for NiO–ZnO heterostructure composite for high dielectric permittivity with low tangent loss for high energy storage applications.

Absence of Weak Localization Effects in Strontium Ferromolybdate

Sr2FeMoO6-δ (SFMO) double perovskite is a promising candidate for room-temperature spintronic applications, since it possesses a half-metallic character (with theoretically 100% spin polarization), a high Curie temperature of about 415 K and a low-field magnetoresistance (LFMR). The magnetic, resistive and catalytic properties of the double perovskite SFMO are excellent for spintronic (non-volatile memory), sensing, fuel cell and microwave absorber applications. However, due to different synthesis conditions of ceramics and thin films, different mechanisms of electrical conductivity and magnetoresistance prevail. In this work, we consider the occurrence of a weak localization effect in SFMO commonly obtained in disordered metallic or semiconducting systems at very low temperatures due to quantum interference of backscattered electrons. We calculate the quantum corrections to conductivity and the contribution of electron scattering to the resistivity of SFMO. We attribute the temperature dependence of SFMO ceramic resistivity in the absence of a magnetic field to the fluctuation-induced tunneling model. We also attribute the decreasing resistivity in the temperature range from 409 K to 590 K to adiabatic small polaron hopping and not to localization effects. Neither fluctuation-induced tunneling nor adiabatic small polaron hopping favors quantum interference. Additionally, we demonstrate that the resistivity upturn behavior of SFMO cannot be explained by weak localization. Here, the fitted model parameters have no physically meaningful values, i.e., the fitted weak localization coefficient (B′) was three orders of magnitude lower than the theoretical coefficient, while the fitted exponent (n) of the electron–electron interaction term (CnTn) could not be assigned to a specific electron-scattering mechanism. Consequently, to the best of our knowledge, there is still no convincing evidence for the presence of weak localization in SFMO.

Adiabatic small polaron hopping conduction in nanostructured Bi2O3–Fe2O3–PbTiO3 prepared by high energy planetary ball mill

Nanostructured 0.52 Bi2O3–0.18 Fe2O3–0.30 PbTiO3 (BFPT) mol% sample was prepared via a high-energy planetary ball mill. To obtain nanostructured materials, the mixture was mechanically milled for 1, 2, 5, and 25 h. The heat treating process was applied to the milled BFPT sample at 673, 873, and 1073 K for 5 h. The amorphous natures of the as-milled and crystallized formed phases of the heat treated samples are examined using the X-ray diffraction (XRD) technique. HRTEM and XRD were used to confirm the amorphous nature and nanocrystallization of the milled and the heat treated BFPT samples, respectively. The effect of the heat-treatment temperature of BFPT samples on their dc electrical conductivity (σ), density (ρ), and oxygen molar volume (Vm) was studied. The results of the thermoelectric power indicate a p-type semiconducting behavior of the BFPT samples. The high temperature (above θD/2) dependent on conductivity was explicated by the small polaron hopping (SPH) model. While Greaves’ variable range hopping (VRH) model was studied at intermediate temperatures. The physical parameters determined from the best fits of these models were thought to be reasonable and consistent with the BFPT samples. The hopping carrier mobility was found to be the dominant factor for determining the conductivity in the BFPT samples. The electronic transport between Fe ions was primarily responsible for the conduction, which was shown to obey the adiabatic SPH.

Effects of Partial Manganese Substitution by Cobalt on the Physical Properties of Pr0.7Sr0.3Mn(1-x)CoxO3 (0 ≤ x ≤ 0.15) Manganites.

We have investigated the structural, magnetic, and electrical transport properties of Pr0.7 Sr0.3 Mn(1-x)Cox O3 nanopowders (x = 0, 0.05, 0.10 and 0.15). The Pechini Sol-gel method was used to synthesize these nanopowders. X-ray diffraction at room temperature shows that all the nano powders have an orthorhombic structure of Pnma space group crystallography. The average crystallite size of samples x = 0, 0.05, 0.10, and 0.15 are 33.78 nm, 29 nm, 33.61 nm, and 24.27 nm, respectively. Semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) confirms the expected stoichiometry of the sample. Magnetic measurements indicate that all samples show a ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. The Curie temperature TC gradually decreases (300 K, 270 K, 250 K, and 235 K for x = 0, 0.05, 0.10, and 0.15, respectively) with increasing Co concentrations. The M-H curves for all compounds reveal the PM behavior at 300 K, while the FM behavior characterizes the magnetic hysteresis at low temperature (5 K). The electrical resistivity measurements show that all compounds exhibit metallic behavior at low temperature (T < Tρ) well fitted by the relation ρ = ρ0 + ρ2T2 + ρ4.5T4.5 and semiconductor behavior above Tρ (T > Tρ), for which the electronic transport can be explained by the variable range hopping model and the adiabatic small polaron hopping model. All samples have significant magnetoresistance (MR) values, even at room temperature. This presented research provides an innovative and practical approach to develop materials in several technological areas, such as ultra-high density magnetic recording and magneto resistive sensors.

Interfacial interaction driven enhancement in the colossal magnetoresistance property of ultra-thin heterostructure of Pr0.6Sr0.4MnO3 in proximity with Pr0.5Ca0.5MnO3

The ultra-thin heterostructure of Pr0.6Sr0.4MnO3(15 nm)/Pr0.5Ca0.5MnO3(15 nm)/SrTiO3 fabricated using pulsed laser deposition technique exhibits the phase-segregated nature wherein the ferromagnetism of Pr0.6Sr0.4MnO3, and the antiferromagnetic state of Pr0.5Ca0.5MnO3 coexist in proximity. The observation of two exciting phenomena in the grown ultra-thin heterostructure, namely, the kinetic arrest and training effect, confirms its phase-segregated nature. The melting of the antiferromagnetic state in Pr0.5Ca0.5MnO3 into a ferromagnetic state due to the interfacial interaction arising from the magnetic proximity of the ferromagnetic clusters of Pr0.6Sr0.4MnO3 have been observed. A metal–insulator transition (TMIT) found at 215 K, close to its Curie temperature (TCurie) observed at 230 K, reveals a strong correlation between the electrical transport and the magnetization of the ultra-thin heterostructure. The electrical conduction in the high-temperature regime is explained in terms of the adiabatic small polaron hopping model. While the resistance in the metallic regime for temperatures above 100 K is contributed by the inelastic scattering due to the two-magnons, in the metallic regime below 100 K, the one-magnon inelastic scattering contribution is prevalent. An enhanced colossal magnetoresistance property near room temperature is obtained in the ultra-thin heterostructure arising from the proximity-driven interfacial interaction, making it a suitable candidate for technological applications near room temperature.

Electrical transport behavior and thermo electric power studies of Nd0.67Sr0.33MnO3/ZrO2 CMR composites

In this work, we reported structural, morphological, electrical, magnetic transport and thermo electric power properties of (1-x) Nd0.67Sr0.33MnO3 - x ZrO2 (abbreviated as NSMO, where × = 0%, 5%, 10%, 15%, and 20% mol.%) composites and were synthesized by a double stage sol–gel method. The X-ray diffraction (XRD) revealed a pure perovskite phase of NSMO. The Scanning electron microscopy (SEM) studies displayed uniform microstructure and the average grain size of NSMO was estimated to be 30 nm and was increased to 80 nm with the substitution of ZrO2. With addition of ZrO2 the metal to insulator transition temperature (Tp) shifted towards lower temperature and the resistivity order of the samples are enhanced from 5 to 10 times. The magnetic transition temperature (Tc) is shifted to higher temperature with increase the ZrO2. The temperature dependent resistivity data is well fitted with polynomial equation, which indicates that the high temperature resistivity behavior has been explored with adiabatic small polaron and variable range hopping (VRH) models.

Influence of Ni content on structural, magnetocaloric and electrical properties in manganite La0.6Ba0.2Sr0.2Mn1-x Ni x O3 (0 ≤ x ≤ 0.1) type perovskites.

We present a detailed study on the physical properties of La0.6Ba0.2Sr0.2Mn1−xNixO3 samples (x = 0.00, 0.05 and 0.1). The ceramics were fabricated using the sol–gel route. Structural refinement, employing the Rietveld method, disclosed a rhombohedral R3̄c phase. The magnetization vs. temperature plots show a paramagnetic–ferromagnetic (PM–FM) transition phase at the TC (Curie temperature), which decreases from 354 K to 301 K. From the Arrott diagrams M2vs. μ0H/M, we can conclude the phase transition is of the second order. Based on measurements of the isothermal magnetization around TC, the magnetocaloric effects (MCEs) have been calculated. The entropy maximum change (−ΔSM) values are 7.40 J kg−1 K−1, 5.6 J kg−1 K−1 and 4.48 J kg−1 K−1, whereas the relative cooling power (RCP) values are 232 J kg−1, 230 J kg−1 and 156 J kg−1 for x = 0.00, 0.05 and 0.10, respectively, under an external field (μ0H) of 5 T. Through these results, the La0.6Ba0.2Sr0.2Mn1−xNixO3 (0 ≤ x ≤ 0.1) samples can be suggested for use in magnetic refrigeration technology above room temperature. The electrical resistivity (ρ) vs. temperature plots exhibit a transition from metallic behavior to semiconductor behavior in the vicinity of TM–SC. The adiabatic small polaron hopping (ASPH) model is applied in the PM-semiconducting part (T > TMS). Throughout the temperature range, ρ is adjusted by the percolation model. This model is based on the phase segregation of FM-metal clusters and PM-insulating regions.

A study on magnetic and spin polarized electric transport properties of cation doped LaCaMnO3perovskite ceramic system

Thepoly-crystallineLa0.5Nd0.15Ca0.35MnO3 has been synthesized by a conventional solid reaction method through the cation doping in LaCaMnO3. The analysis of the powder XRD of the composites revealed the formation of an orthorhombic structure in Pbnm space group. The cell parameters of the formed system has obtained and confirmed through Reitveld analysis and it is found to be a=5.4505,b=5.4457,c=7.6876.The lattice parameters and the spin ordering temperature TC of this system are decreasing due to Nd substitution. The ac and dc magnetization studies and resistivity measurements in ZFC and FC mode gives good understanding to the magnetic and electric transport properties of the doped system. The magnetization studies show a paramagnetic to ferromagnetic transition at a temperature below the critical temperature TC.The resistivity measurements reveals semiconducting to metallic transition below the temperature TMS. The temperature dependent transport nature shown in this system is one type of the correlated polaron hopping mechanism and it can be modeled by an adiabatic small polaron hopping(SPH) mechanism.

Two conductive mechanisms in LaMnO3 thin film: Adiabatic and nonadiabatic small polaronic hopping

We have presented the structural, surface morphology, magnetic and resistivity data for perovskite LaMnO3 epitaxial thin films which are fabricated on well-oriented (001) LaAlO3 substrates by pulsed laser deposition technique. X-ray diffraction [Formula: see text]–[Formula: see text] linear scans and reciprocal space mapping measurement confirm that the out-of-plane and in-plane epitaxial relationship are LMO(001)/LAO(001) and LMO(110)/LAO(110), respectively. Surface roughness determined by atomic force microscopy was no more than 0.3 nm. In the whole studied temperature range, all films only show a paramagnetic behavior instead of any magnetic phase transitions. Correspondingly, the electron transport behaviors always exhibit an insulting state as the temperature changes from high to low. However, we find that none of theoretical models can individually be used to understand their conductive mechanisms. Further studies indicated that charge carries of high and low temperature region obey adiabatic and nonadiabatic small polaronic hopping mechanisms, respectively. This finding offers new ways of exploiting the abnormal ferromagnetism in LaMnO3 multilayer thin films.

Studies on Colossal Magnetoresistance Behaviour of Pr0.6Sr0.4MnO3/Pr0.5Ca0.5MnO3 Heterostructure Films

Heterostructure bilayer thin films of Pr0.6Sr0.4MnO3/Pr0.5Ca0.5MnO3 were prepared by pulsed laser deposition, and the structural, magnetic and magnetotransport properties were studied, and the results were compared to that of Pr0.6Sr0.4MnO3 and Pr0.5Ca0.5MnO3 single-layer thin films. Structural analysis of the heterostructure reveals c-axis orientation for both the manganite layers. The heterostructure exhibits a higher metal-insulator transition temperature and a larger colossal magnetoresistance near room temperature than that of the single-layer counterparts. The electrical conduction above the metal-insulator transition could be explained within the realm of the adiabatic small polaron hopping mechanism, with lesser activation energies compared to the single-layer films. Magnetization measurements portray the presence of an unsaturated symmetric hysteresis loop for the heterostructure with the Curie temperature of ~270 K corresponding to the ferromagnetic ordering emanating from Pr0.6Sr0.4MnO3. These results could be qualitatively understood considering the combined effect of strain and ferromagnetic proximity of Pr0.6Sr0.4MnO3 with charge-ordered Pr0.5Ca0.5MnO3 manganite.

A-site Pb doping effect on structural, microstructural and magnetotransport properties of La0.5Sm0.2Ca0.3-xPbxMnO3 (x=0, 0.05, 0.10) manganite

Structural, microstructural and magneto-transport properties of polycrystalline La0.5Sm0.2Ca0.3-x PbxMnO3 (x = 0, 0.05 and 0.10) samples, prepared by conventional solid state reaction, were studied. Refinement of the Powder X-ray diffractograms revealed that all the samples crystallize into orthorhombic structure with Pnma space group and the lattice parameters increase with increasing Pb content. The scanning electron microscope (SEM) micrographs show a granular character and the estimated grain sizes ranges between 10 μm and 20 μm. The experimental electrical resistivity and the magnetoresistance in the temperature range 20 K–250 K under magnetic field of zero and 1 Ta, have been recorded using four probe technique. The resistivity curves without magnetic field, exhibit a ferromagnetic-metallic (FM) to paramagnetic-insulating (PI) transition at TMI = 125 K, 91 K and 37 K for x = 0, 0.05 and 0.10, respectively. The magnetoresistance reaches 58% for undoped sample and decrease with Pb doping under 1T. The resistivity values increases drastically with Pb doping. These two results were explained mainly by the increase of the disorder σ2 and <rA>. In the low temperature range (T < TMI) and for x = 0 and 0.05 samples, the resistivity curves is well fitted by a combination of the residual resistivity, weak localization and electron-electron scatterings; in addition to small polaron contribution or electron-phonon interaction respectively. In the high temperature regime T > TMI, all our resistivity curves has been analyzed using adiabatic small polaron hopping model (ASPH) above θD/2 and variable range hopping model (3D-VRH) (TMI < T < θD/2). An attempt to use the percolation model to describe the resistivity data in the entire temperature range for both x = 0 and 0.05 samples, was established. Finally, density of state, mean hopping distance Rh and mean hopping energy Eh were calculated and discussed.

High-temperature polaronic transport in PrBaCoTa(Nb)O6 perovskite-like phases

The electrical transport properties of dense PrBaCoTaO6 and PrBaCoNbO6 polycrystalline phases are thoroughly studied. Both measured conductivity and thermopower temperature dependencies are consistent with p-type adiabatic small polaron hopping mechanism. Detailed analysis based on DFT calculations reveals Co t2g orbitals play crucial role in charge transfer process. The proposed theoretical transport model predicts most trivalent Co ions tend to acquire an intermediate spin state acting as self-trapped electron holes. Estimated carrier mobility and polaron jump frequency values for both studied compounds are found to be in a reasonable coincidence with previously obtained results.

Charge transport mechanism and percolation model in La0.75Ca0.25−xNaxMnO3 (0 ≤ x ≤ 0.10) manganites

In this communication, La0.75Ca0.25−xNaxMnO3 (0 ≤ x ≤ 0.10) samples were synthesized by the Flux method and their structural and electrical properties were systematically undertaken. X-ray diffraction of the samples showed an orthorhombic structure with a Pbnm space group. Furthermore, to get a better understanding of the electrical properties, the resistivity ρ(T) as a function of temperature was measured by a standard four-probe method. The maximum resistivity values decreased and the insulator–metal transition temperature (TM–SC) increased with increasing magnetic field. At low-temperature region (T TM–SC) region, the transport mechanism was explained using the adiabatic small polaron hopping and the variable-range hopping models. Then, to get insights into the change in the resistivity plots, in entire temperature, ρ(T) was fitted by the percolation model. Interestingly, it is important to note that the activation energy (Ea) decreased with increasing Na+ content, which indicates the enhancement of the double-exchange (DE) interaction. Moreover the magnetoresistance (MR %) effect was studied.

Study of magnetic and magnetoresistance behaviour of [formula omitted] composites

Nanocomposites of Lanthanum Strontium Manganite and Cobalt Ferrite with different weight percentages were prepared using the sol–gel method and sintered at 950 °C. Presence of constituent phases of La0.67Sr0.33MnO3 and CoFe2O4 peaks were confirmed from X-ray diffraction and Fourier transform infrared spectroscopy studies. Hysteresis behaviour shows room ferromagnetism for the composite samples and their variation in saturation magnetization can be understood on the basis of competing effects between both the magnetic phases. Enhancement of squareness ratio and coercivity indicate the strengthening of exchange-coupling interaction due to closer proximity of hard and soft phases. Metallic state vanishes and resistivity increases with the incorporation of cobalt ferrite into lanthanum strontium matrix. An enhanced magnetoresistance in a wide temperature range is observed for 25% cobalt ferrite added sample and is ascribed to spin-polarized tunneling mechanism. Adiabatic small polaron hopping mechanism is used to explain the resistivity of the composites in the high temperature region.

Investigation of cationic disorder effects on the transport and magnetic properties of perovskite [formula omitted] ([formula omitted]; RE = Nd, Sm, & Gd)

The strong influence of the A-site cationic size mismatch on the electrical, thermal and magnetotransport properties of Pr0.7-xRExSr0.3MnO3 (x=0.0,0.2; RE = Nd, Sm & Gd) pervoskite compound has been reported here. The considerable shifting of the insulator to metal transition temperature (TIM) with the partial substitution of Pr3+ ions by smaller radii rare-earth ions is discussed. The relevance of electron-electron scattering and the application of an adiabatic small polaron hopping (ASPH) model is explained to analyze electrical data. The temperature dependent volume fraction of the metallic ferromagnetic phase obtained from the percolation model of the electrical resistivity demonstrated a well resemblance with magnetic data. Analysis of Thermoelectric Power (TEP) data reveals that electron-magnon scattering is responsible for the thermoelectric transport in the metallic region whereas high temperature insulating region above Tp is well explained by the non-adiabatic SPH model.

Electrical and thermal properties of Pr0.6Sr0.4\u2212xAgxMnO3 (x\u2009=\u20090.05 and 0.1) manganite

Monovalent silver-doped Pr0.6Sr0.4−xAgxMnO3 manganite has been chosen for the electrical and thermal transport studies. The electrical measurements confirmed a metal–insulator transition around room temperature. For the analysis of the resistivity data, in the high-temperature paramagnetic region, the adiabatic small polaron hopping model was operative. The magnetoresistance studies, under different external magnetic field, showed that the MR peak is located at the metal–insulator transition and ferromagnetic–paramagnetic transition, which is characteristic for an intrinsic magnetoresistance. The thermal conductivity results exhibit a semicrystalline character with grain boundary scattering as a main mechanism limiting the heat transfer in samples. The electrical contribution to the thermal conductivity is relatively small, around 1%, as in most of the manganites. The transition point around room temperature is also visible. The additionally calculated thermal diffusivity parameter shows values of the order typically found in perovskites.

High magnetoresistance in La0.5Nd0.15Ca0.25A0.1MnO3 (A = Ca, Li, Na, K) CMR manganites: Correlation between their magnetic and electrical properties

The influence of A-site cation disorder of monovalent alkali ions on structural and magneto-transport properties of colossal magnetoresistive (CMR) materials has been reported. All the compounds crystallize in Pbnm space group with orthorhombic symmetry. At low temperature, the samples exhibit a paramagnetic (PM) to ferromagnetic (FM) transition and a semiconductor to metallic one. The variation in both Curie temperature (Tc) and metal-semiconductor transition temperature (TMS) can be explained by the change in Mn4+ content and average A-site cation radius. A decrease in resistivity in the vicinity of TMS has been observed with an increase in the applied magnetic field. The values of Tc are close to TMS, signifying strong correlations between the magnetic and electrical properties. The electrical resistivity data in paramagnetic-semiconducting region (T >TMS) may be described by the adiabatic small polaron hopping (ASPH) model. Maximum magnetoresistance (MR%) has been observed in the vicinity of TMS.

Low temperature anomalies and room temperature magnetism in In0.95Fe0.05Sb dilute magnetic semiconducting film

We report the results of structural, electrical, surface morphological, and magnetic studies on the undoped and dilute Fe (0.05) doped InSb films (In0.95Fe0.05Sb) using the grazing angle X-ray diffraction technique, the quantum design physical property measurement system, atomic force microscopy (AFM), magnetic force microscopy (MFM), and the quantum design magnetic property measurement system. The In0.95Fe0.05Sb film of 500 nm thickness is grown on the silicon (Si) substrate using the thermal evaporation technique. A systematic investigation of electrical resistivity as a function of temperature and magnetic field is embarked. The electrical resistivity of the respective sample exhibits an upturn at approximately 15 K in the ferrimagnetic region. This theory explains the anomalous behavior of the electrical resistivity based on electron-electron, electron-phonon, electron-magnon, and Kondo-like spin-dependent scattering. The high-temperature data above 300 K are interpreted using the adiabatic small polaron hopping model. The AFM study shows the uniform particle size distribution, whereas the magnetic interaction at the surface is seen through MFM. The zero-field cooled magnetization measurement shows the transition at ∼65 K. The hysteresis curve at 10 K shows the ferrimagnetic behavior of the In0.95Fe0.05Sb film with coercivity and residual magnetization values of ∼100 Oe and 6.8811 emu, respectively.

Structural and electrical characterizations of hydrothermally grown hydroxyapatite polycrystals: A morphological hierarchy

Pure hydroxyapatite (HAp) semiconducting microrods with very low dielectric loss have been synthesized in aqueous media of pH values 6, 8, and 10 by the hydrothermal method. Samples are characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectra analyses. The optical bandgap energies of these samples are found to be within the semiconducting range (∼3–4 eV). FESEM and TEM image analyses reveal the formation of microrods and reduction of the average length of the rods with increasing pH values. A core-shell-like microrod structure has been observed in the sample with pH value 6. The charge carrier follows an adiabatic small polaron hopping mechanism. The dielectric loss values are very small compared to that of other ceramic oxides which is very advantageous for electronic applications. Correlated barrier hopping model is the dominant charge transport mechanism within the samples with maximum barrier heights of 0.25 eV, 0.26 eV, and 0.27 eV for samples with pH values 6, 8, and 10, respectively. Nonideal Debye type relaxation appears within the material when the AC field is applied for temperatures above 100 °C.

Comparison of structural, magnetic and electrical transport behavior in bulk and nanocrystalline Nd-lacunar Nd0.67Sr0.33MnO3 manganites

Abstract Bulk and nanocrystalline Nd-lacunar Nd0.67Sr0.33MnO3 manganites were synthesized, and the structural, magnetic and electrical properties have been systematically studied. The Rietveld refinement confirms perovskite structure with orthorhombic crystal symmetry (Pbnm space group). The bulk compound shows a sharp second order transition at 275 K while the nanocrystalline compound exhibit a broadened transition with a TC of 242 K. Temperature dependence of electrical resistivity of both the compounds witness double peaks; a sharp peak near TC and a broad peak below TC, which is more prominent in the nanocrystalline compound whereas former peak is more prominent in the bulk compound. The combined effect of Kondo-like spin-dependent scattering and electron-electron interactions dominates the transport properties at low temperature in the nanocrystalline compound and results in upturn enhancement in resistivity, while the high-temperature insulating behavior of both compounds can be explained by the adiabatic small polaron hopping mechanism. The effective Mn ion valence of bulk and nanocrystalline compounds are found to be 3.56 and 3.25 and the observed crystal field splitting energy is slightly higher for the nanocrystalline compound. X-ray absorption spectra result quantitatively demonstrates that the broken symmetry at the surface of nanocrystalline compound aid to stabilize more Mn3+ ions that lead to interesting magnetic and electrical transport behavior.