Mamatha Daivajna

Mamatha Daivajna
Manipal Academy of Higher Education | MAHE · Department of Physics

About

20
Publications
1,912
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156
Citations
Citations since 2016
15 Research Items
140 Citations
2016201720182019202020212022051015202530
2016201720182019202020212022051015202530
2016201720182019202020212022051015202530
2016201720182019202020212022051015202530

Publications

Publications (20)
Article
The bismuth (Bi)-substituted La0.85-xBixNa0.15MnO3 (x = 0 and x = 0.1) manganites have been investigated for achieving room temperature magnetic entropy change at low magnetizing intensities. A 10% Bi ion substitution at the La site has led to the relatively higher symmetry R3̄c rhombohedral structure showing improvement in Mn-O-Mn bond angles. The...
Article
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Polycrystalline bulk Barium hexaferrite, BaFe12O19 were synthesised by ball milling for different milling duration followed by sintering at high temperature. Effect of milling duration on structural, morphological and dc electrical properties were studied for 4, 8, 12 and 16 h of milling using planetary ball mill. X-ray diffraction measurement data...
Article
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Magnetic phase coexistence in the substituted perovskite compound, La0.4Bi0.3Sr0.3MnO3, is attributed to the spontaneous moment and a step-like metamagnetic transition observed in the magnetization measurements in its magnetically order state. The magnetism of samples reduced to nanometer sizes by the “top down” approach exhibits interesting change...
Article
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The effect of particle size reduction on the magnetic correlations of Pr 0.4 Bi 0.2 Sr 0.4 MnO 3 nanoparticles prepared by top-down approach has been studied in detail. It was observed that as the milling time increases from 0 to 240 min, particle size decreases from 160 to 12 nm. Correspondingly it was observed that the ferromagnetic transition te...
Article
Full-text available
We report the structural, magnetic, and magnetocaloric properties of Bismuth (Bi)-substituted manganite La 0.85-x Bi x Na 0.15 MnO 3 ( x =0, 0.1, 0.2, 0.25, and 0.3). X-ray diffraction data implicates the rhombohedral structure with $$ R\overline{3}c $$ R 3 ¯ c space group. Bi 2 O 3 has helped in ensuring phase pure, densified compounds even at low...
Article
In the present investigation, we have made an effort to synthesize and study the structure of Yb substituted Pr0.67-xYbxCa0.33MnO3 (PYCMO) [x = 0.0, 0.09, 0.2, 0.4 and 0.6] manganites. The tolerance factor estimated decreases while the A-site variance increases with an increase in Yb concentration. This gives an insight of the impact of Yb on the s...
Article
This study focuses on the effects of the substitution of a nonmagnetic ion on the structure, magnetism, and thermoelectric power of binary La0.85−xBixK0.15MnO3 (x = 0, 0.15, 0.3) manganites synthesized via a ceramic route. Structural analysis reveals a dual crystallographic phase in the system, which results due to charge disproportionation. The co...
Article
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The structural and magneto-transport properties of polycrystalline La0.85–xBixNa0.15MnO3, (x = 0, 0.05, 0.1, 0.2) manganites are reported. The polycrystalline samples were prepared using solid-state synthesis route. Rietveld refinement of X-ray data conclude the samples crystallized in a rhombohedrally distorted structure belonging to \( R\overline...
Article
Full-text available
Low temperature magnetization and resistivity measurements of bismuth (Bi) doped Pr0.6−xBixSr0.4MnO3 (x = 0.2, 0.23 and 0.25) manganites synthesized by solid state reaction method are reported here. Resistivity measurements in all bismuth doped samples in the absence of field show no significant metal–insulator transition. But for x = 0.2, in zero...
Article
We present temperature-dependent studies on electrical and thermal properties of bulk samples of Pr2/3Sr1/3MnO3-δ synthesized at different sintering temperatures (TS). It is established that these properties intensely influenced by the sintering temperatures. Analysis of electrical resistivity data ρ(T) by means of standard models, demonstrated tha...
Article
In the present work we report structural, electrical, magnetic and thermo-power of Pr0.8-xDyxSr0.2MnO3 with (x = 0, 0.2 and 0.25) manganites. It is observed that Curie temperature TC decreases with Dy doping and also ZFC magnetization curves decrease more sharply with Dy from magnetization study. Though, Dy³⁺ ion has large magnetic moment μ = 10.65...
Article
In the present investigation structural, magneto-transport, magnetic and thermo-power measurements of Gadolinium (Gd) doped Pr0.8-xGdxSr0.2MnO3 (0, 0.2, 0.25 and 0.3) manganites have been done. All the samples are single phased with orthorhombic structure. Temperature variation of resistance exhibits a high temperature transition occurring at 156 K...
Article
We have investigated the electrical and magnetic properties of Pr0.6-xBixSr0.4MnO3 (x = 0.20 and 0.25) manganites. XRD data shows that the synthesized samples are single-phase and crystallize in the orthorhombic structure with Pnma space group. Resistivity measurements show that the sample with x = 0.25 exhibits a thermally activated behavior for t...
Article
Near room temperature, magnetocaloric effect in pristine and Bi-doped Pr0.6Sr0.4MnO3 manganites has been studied using in-field heat capacity measurements. The Debye temperature (θD) for the pristine sample was estimated to be 522 K and its value increases to 530 K for the Bi-doped sample with x=0.05. The entropy associated with paramagnetic (PM) t...
Article
In the present investigation detailed electrical, magnetic and thermoelectric measurements on Bi-doped L0.6−xBixSr0.4MnO3 (0≤x≤0.3) manganites have been done. All the samples are single phased. The metal-insulator transition temperatures (TMI) as well as the Curie temperature (TC) are both found to decrease with Bi-content. Magneto-resistance (MR)...
Article
We report detailed electrical, magnetic and thermoelectric studies on Bi-doped L0.7−xBixSr0.3MnO3 (0 ⩽ x ⩽ 0.25) manganites. The XRD patterns and Rietveld analysis show that the studied materials are single phased. All the compounds, exhibit the expected metal-insulator transition and a decrease in the characteristic metal-insulator transition temp...
Article
Electrical and thermal properties of Bi-doped Pr0·7 Sr0·3 MnO3 (PSMO) compounds are reported here. It is observed that Bi-doped PSMO compounds follow variable range conduction mechanism. Specific heat, thermal conductivity and thermo-power measurements show that larger Bi-ion, in place of smaller Pr ion, enhances their transition temperatures (T MI...
Article
Magneto-resistance effects of Bi doped Pr1-xSr0.3Mno3 (x=0.00, 0.15,0.20, 0.25) at different magnetic fields have been studied The samples were prepared by solid state reaction method and structural characterization was done by X-ray diffraction (XRD). It is observed that increase in magneto-resistance ratio with increase in magnetic field and decr...

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Project (1)
Project
To study the Charge Ordering in nanoparticles of Bi doped manganites prepared by top down approach.