Journal ArticleDOI
Electrical transport properties and magnetic cluster glass behavior of Nd0.7Sr0.3MnO3 nanoparticles
B. Roy,Asok Poddar,S. Das +2 more
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In this article, the transport and magnetic properties of Nd07Sr03MnO3 nanoparticles were investigated by the sol-gel method and the results showed that resistivity increases with the decrease of the particle size due to the enhancement of the grain boundary effect.Abstract:
The transport and magnetic properties have been investigated in Nd07Sr03MnO3 nanoparticles prepared by the sol-gel method The resistivity (ρ) increases with the decrease of the particle size due to the enhancement of the grain boundary effect ρ(T) shows two distinct transitions for all the samples such as metal-insulator transition and transition due to the barrier caused by the grain boundary effect The thermopower (S) is found to be negative and at high temperature S follows the adiabatic small polaron hopping theory In the metallic region the spin wave contribution is found to be dominant in the temperature dependence of the thermopower The magnetoresistance (MR) of the ultrafine particles increases with the decrease of particle size indicating substantial contribution from the grain boundaries Spin polarized intergrain tunneling effect plays an important role in the MR of a smaller size particle, whereas in the case of samples of higher dimension spin fluctuation contributes predominantly Theread more
Citations
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Magnetoresistive properties of Ni-doped La 0.7 Sr 0.3 MnO 3 manganites
Ahmed Mohamed Ahmed,Abd El-Moez A. Mohamed,Medhat Abdelrady Abdellateef,Hassan Ahmed Abd El-Ghanny +3 more
TL;DR: In this article, the authors used the small polaron hopping (SPH) and the variable range hopping (VRH) models to examine conduction in the semiconducting region.
Journal ArticleDOI
Magnetic cluster glass behavior and grain boundary effect in Nd0.7Ba0.3MnO3 nanoparticles
TL;DR: In this article, the magnetic and transport properties of Nd0.7Ba0.3MnO3 nanoparticles were explored by transmission electron microscopy, x-ray powder diffraction, resistivity, magnetoresistance, thermopower (S), and magnetic measurements.
Journal ArticleDOI
Magnetic Properties of Interacting La 0.67 Sr 0.33 MnO 3 Nanoparticles
Abstract: Magnetic nanoparticles of La0.67Sr0.33MnO3 (LSMO) with mean particle sizes of 13, 16, 18, and 21 nm were prepared by the sol–gel method. The samples were characterized by X-ray diffraction (XRD) using Rietveld refinement and transmission electron microscope (TEM). Fourier transform infrared (FTIR) transmission spectroscopy revealed that stretching and bending modes are influenced by annealing temperature. Dc magnetization versus magnetic field of the samples was carried out at room temperature. Magnetic dynamics of the samples was studied by the measurement of ac magnetic susceptibility versus temperature at different frequencies and ac magnetic fields. A frequency-dependent peak was observed in ac magnetic susceptibility versus temperature which is well described by Vogel–Fulcher and critical slowing down laws, and empirical $c_{1} = \frac{\Delta T_{f}}{T_{f}\Delta (\log _{10}f)}$
and $c_{2} = \frac{T_{f} -T_{0}}{T_{f}}$
parameters. By fitting the experimental data with Vogel–Fulcher magnetic anisotropy energy and an effective magnetic anisotropy constant have been estimated. The obtained values support the presence of strong interaction between magnetic nanoparticles of LSMO.
Journal ArticleDOI
Size-induced metal insulator transition and glassy magnetic behavior in La0.5Sr0.5CoO3 nanoparticles
TL;DR: In this article, structural, electrical, and magnetic properties of La0.5Sr0.3 nanoparticles prepared by sol-gel technique are investigated and the results reveal a size-induced metal insulator transition in the electrotransport behavior.
Journal ArticleDOI
Structural and electrical properties in La1−xLixMnO3
Sayed A. Ahmed,Sayed A. Ahmed +1 more
TL;DR: Li-substituted perovskites La 1− x Li x MnO 3 (LLMO; 0.05≤ x ≤ 0.25) were investigated by X-ray diffraction, electric resistivity and magnetoresistance (MR) measurements.
References
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Journal ArticleDOI
Semiconductor Clusters, Nanocrystals, and Quantum Dots
TL;DR: In this article, the authors focus on the properties of quantum dots and their ability to join the dots into complex assemblies creates many opportunities for scientific discovery, such as the ability of joining the dots to complex assemblies.
Journal ArticleDOI
Metal-insulator transitions
TL;DR: A review of the metal-insulator transition can be found in this article, where a pedagogical introduction to the subject is given, as well as a comparison between experimental results and theoretical achievements.
Journal ArticleDOI
Double exchange alone does not explain the resistivity of La1-xSrxMnO3.
TL;DR: It is proposed that in addition to double-exchange physics a strong electron-phonon interaction arising from the Jahn-Teller splitting of the outer Mn $d$ level plays a crucial role.
Journal ArticleDOI
Studies of polaron motion: Part II. The “small” polaron
TL;DR: In this article, the authors considered the case in which the electronic-overlap term of the total Hamiltonian is a small perturbation, and showed that the probability of off-diagonal transitions goes up exponentially with increasing temperature.
Journal ArticleDOI
The physics of manganites: Structure and transport
M. B. Salamon,Marcelo Jaime +1 more
TL;DR: The fundamental physical properties of doped oxides and their underlying physics were known more than 40 years ago as mentioned in this paper, and the concept of double exchange in particular, and points out the missing elements that have led to a massive resurgence of interest in these and related materials.