Size mismatch, grain boundary and bandwidth effects on structural, magnetic and electrical properties of Pr0.67Ba0.33MnO3 and Pr0.67Sr0.33MnO3 perovskites

We have investigated the electrical properties of La 0.6 Pr 0.1 Ba 0.3 Mn 1-x Ni x O 3 (x = 0 and x = 0.1) nanocrystalline manganites using complex impedance spectroscopy technique in 40Hz-10 kHz and 80-320 K, frequency and temperature ranges, respectively. The two samples exhibit a metal-semiconductor transition temperature T MS which decreases from 160 to 120 K when increasing Ni content from x = 0 to x = 0.1. The total conductance curves for samples are found to obey Jonscher power law G(x) = G DC ? Ax n . The Ni content affects the activation energy (E a ) which increases from 37 meV for x = 0 to 48 meV for x = 0.1. The obtained n exponent values for x = 0 are higher than those obtained for x = 0.1. This can be related to the decrease in grain size when Ni content increases. Nyquist plots of impedance show semicircle arcs for samples, and an electrical equivalent circuit has been proposed to explain the impedance results.

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“…-O 2--Mn 4? , which increases the energy gap and leads to lower DC conductance in x = 0.1 than in x = 0 [20,21].…”

Section: Low-frequency Behaviormentioning

confidence: 99%

Electrical conductance and complex impedance analysis of La0.6Pr0.1Ba0.3Mn1−xNixO3 nanocrystalline manganites

et al. 2015

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“…Tolerance factor (t) was calculated by using equation : ( 1 ) where r A , r B , and r O are the radii of A 3+ , B 3+ , and O 2− ions in ABO 3 perovskite, respectively. Tolerance factor calculation results confirm that the stable crystal structure is orthorhombic perovskite structure (0.89≤ t ≤0.96) [9]. As shown in [14].…”

Section: Introductionmentioning

confidence: 53%

“…Hence, Mixed valence Mn 3+ /Mn 4+ ions play a very important role in the electric and magnetic properties of lanthanum manganites [4]. The electrical and magnetic properties are also affected by the avarage A-site cation radius < r A > and the A-site cation size mismatch [3,9]. Those induce distortion of MnO 6 octahedron thereby change the the distance and angle between Mn-O-Mn ions [10].…”

Section: Introductionmentioning

confidence: 99%

The structural, morphological and magnetic properties of Ag-doped La_0.8Ca_0.2-xAg_xMnO₃ synthesized by sol-gel method

Ruli

Kurniawan²

2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. In this paper, The authors report the structural, morphological and magnetic properties of La 0.8 Ca 0.2-x Ag x MnO 3 (x = 0, 0.03) prepared by sol-gel method. The X-ray diffraction (XRD) patterns of samples reveal an orthorhombic perovskite structure with a space group Pnma. The lattice parameters, Mn-O bond length and unit cell volume increase with doping Ag whereas Mn-O-Mn angle decrease. The scanning electron microscopy (SEM) images show thatLa 0.8 Ca 0.2 MnO 3 sample more porous than La 0.8 Ca 0.17 Ag 0.03 MnO 3 sample. Analysis using energy dispersive X-ray (EDX) confirms that there is no significant difference between designated and measured composition. M-H loop hysteresis indicate both sampleare paramagnetic materials which La 0.8 Ca 0.17 Ag 0.03 MnO 3 sample has higher susceptibility than the others.

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“…We noted also that the T P values of our specimens are lower than T C values (see table 3). Such difference is often attributed to the grain boundary effects [18,19]. Other studies suggest that the doping level in the A-site [20] as well as oxygen deficiency [19,21] play an important role for the observed electrical behaviour.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, structural, magnetic and electrical properties of nominal La_0.67Ba_0.33-xNa_xMnO₃(0 ≤ x ≤ 0.33) manganites

Hcini

Zemni

Boudard

et al. 2012

EPJ Web of Conferences

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Abstract.Complete nominal solid solutions La 0.67 Ba 0.33-x Na x MnO 3 (0 ≤ x ≤ 0.33) have been elaborated by ceramic route at 1200°C. ICPAES chemical analysis and XRD Rietveld structure refinement revealed that the nominal Na content is not achieved by our ceramic method. The chemical formula should be rather written as La α Ba β Na λ MnO 3-δ with a significantly lower Na content (λ), than the nominal one (x), and with a slight deficit (δ) in oxygen content, leading to the appearance of two minor secondary phases identified as Mn 3 O 4 and Na 0.55 Mn 2 O 4 . 1.5H 2 O. Magnetization and electrical resistance vs. temperature show paramagnetic/semiconductor -ferromagnetic/metallic transitions with only a slight decrease in magnetic and electrical transition temperatures when Na content increases. Such amount of this decrease is not expected according to the nominal Na content giving a significant difference between nominal and experimental Mn 4+ /Mn 3+ ratios.

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Size mismatch, grain boundary and bandwidth effects on structural, magnetic and electrical properties of Pr0.67Ba0.33MnO3 and Pr0.67Sr0.33MnO3 perovskites

Cited by 91 publications

References 30 publications

Electrical conductance and complex impedance analysis of La0.6Pr0.1Ba0.3Mn1−xNixO3 nanocrystalline manganites

Electrical conductance and complex impedance analysis of La0.6Pr0.1Ba0.3Mn1−xNixO3 nanocrystalline manganites

The structural, morphological and magnetic properties of Ag-doped La_0.8Ca_0.2-xAg_xMnO₃ synthesized by sol-gel method

Synthesis, structural, magnetic and electrical properties of nominal La_0.67Ba_0.33-xNa_xMnO₃(0 ≤ x ≤ 0.33) manganites

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Size mismatch, grain boundary and bandwidth effects on structural, magnetic and electrical properties of Pr0.67Ba0.33MnO3 and Pr0.67Sr0.33MnO3 perovskites

Cited by 91 publications

References 30 publications

Electrical conductance and complex impedance analysis of La0.6Pr0.1Ba0.3Mn1−xNixO3 nanocrystalline manganites

Electrical conductance and complex impedance analysis of La0.6Pr0.1Ba0.3Mn1−xNixO3 nanocrystalline manganites

The structural, morphological and magnetic properties of Ag-doped La0.8Ca0.2-xAgxMnO3 synthesized by sol-gel method

Synthesis, structural, magnetic and electrical properties of nominal La0.67Ba0.33-xNaxMnO3(0 ≤ x ≤ 0.33) manganites

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The structural, morphological and magnetic properties of Ag-doped La_0.8Ca_0.2-xAg_xMnO₃ synthesized by sol-gel method

Synthesis, structural, magnetic and electrical properties of nominal La_0.67Ba_0.33-xNa_xMnO₃(0 ≤ x ≤ 0.33) manganites