In this work, we have studied structural, electro-magnetic and magnetocaloric properties of La0.7Ba0.3MnO3/ xTiO2 manganite/insulator system with 0 x 0.08. X-ray diffraction (XRD) shows the coexistence of TiO2 and La0.7Ba0.3MnO3 phases in doped composites through their characteristic peaks. This reveals their interaction lack preserving the R-3c rhombohedral structure for all composites. Due to interaction lack, TiO2 is suggested to segregate ... إقراء المزيد

The effect of annealing temperature on structural, electrical and magnetic properties of bulk (Nd0.6Sr0.4MnO3)0.99/(CrO3)0.01 and (Nd0.6Sr0.4MnO3)0.98/(CrO3)0.02 compositions are investigated. X-ray diffraction show that (Nd0.6Sr0.4MnO3)1-x/(CrO3)x(NSMOC) crystallize in a single-phase rhombohedral structure for the as-prepared and annealed samples. Electrical measurement show a metal-semiconductor transition temperature (Tms) for the two compositions. It is observed that Tms increases with thermal treatment. The magnetoresistance MR ... إقراء المزيد

Magnetocaloric-transport properties correlation in doped manganites إقراء المزيد

La0.7Sr0.3Mn1−_x_ Ni _x_ O3 (_x_ = 0, 0.025, 0.050 and 0.075) ceramics were prepared by the conventional solid-state reaction method. The partial substitution of Mn by Ni2+ leads to a decrease in cell volume as well as a structural transition from the rhombohedral to the orthorhombic structure. Ni2+ doping increases the electrical resistivity, decreases the semiconductor–metal transition temperature (_T_ ms) ... إقراء المزيد

The effect of annealing temperature on structural, electrical and magnetic properties of bulk (Nd0.6Sr0.4MnO3)0.99/(CrO3)0.01 and (Nd0.6Sr0.4MnO3)0.98/(CrO3)0.02 compositions are investigated. X-ray diffraction show that (Nd0.6Sr0.4MnO3)1-x/(CrO3)x(NSMOC) crystallize in a single-phase rhombohedral structure for the as-prepared and annealed samples. Electrical measurement show a metal-semiconductor transition temperature (Tms) for the two compositions. It is observed that Tms increases with thermal treatment. The magnetoresistance MR ... إقراء المزيد

In this work, we investigate the effect of interface size on the electrical, magnetoresistive, magnetic and magnetocaloric properties of the La0.7Ba0.3MnO3 (LBMO) manganite compound. This is done by introducing different sizes of secondary phases of Ni and Ag (Ni powder, Ni nanowires, Ag oxide powder and Ag nanoparticles) to the LBMO compound, forming inhomogeneous systems of LBMO/Ni and LBMO/Ag composites. ... إقراء المزيد

This investigation is mainly concerned with the effect of annealing temperature (600, 700, 800 and 900 °C) in air for (La0.7Ba0.3MnO3)1–x/(NiO)x with x = 0 and x = 0.10 samples. It was shown that the annealing temperature does not affect the structure and parameters of rhombohedral lattice of the samples. However, it is observed that the annealing treatment has a ... إقراء المزيد

(La0.7Sr0.3MnO3)1-x/(ZrO2)x (x = 0.0–0.150, step 0.025) composites have been prepared via solid state reaction process. The X-ray diffraction and scanning electron microscopic observations indicate that there are ZrO2 grains separated from La0.7Sr0.3MnO3 matrix. It has been found that the inclusion of ZrO2 content decreases the conductivity, magnetization and metal–semiconductor transition, whereas it increases the low field magnetoresistance. Possible effects of ... إقراء المزيد

Wepresentresultsofacomprehensiveinvestigationofthestructural,frequencydependentacsus- ceptibility,dcmagnetization,magnetoresistanceandthermoelectricpowermeasurementsonpoly- crystalline samplesofLa1xLixMnO3 (0.05rxr0.30). Allsamplesundergoferromagnetictopara- magnetic transitionandmetaltosemiconductortransition.Acuspinthezero field-cooled indcmag- netization andafrequency-dependentpeakintheacsusceptibilityrevealtheglassybehaviors.Theoutof phase componentoftheacsusceptibilityshowsfrequency-dependentpeaksbelowtheCurietempera- ture (indicativeofglassybehavior)whichhavepreviouslybeeninterpretedintermsoffreezingof clusters. Thegrainboundariesplayadominantroleintheconductionprocess.Theframeworkofthe magnon andphonondragconceptanalyzedthermoelectricpowerdataatlowtemperature,whilesmall polaron conductionmechanismexplainedthermoelectricpowerdataathightemperature.Ithasbeen found thatthepercolationthresholdsampleis x¼0.10,sotheauthor’s pointofviewreferstomakespot on thissampleinthefutureworks. إقراء المزيد

In thiswork,Zn100xInx (x¼0, 1,2.5,5and7.5at%)compoundshavebeeninitiallyalloyedbymeltingmethodandusedasprecursorsto prepare differentnanostructuresofindium(In)dopedZnOusingchemicalvapordeposition(CVD).TheeffectofIncontentonthestructural, morphological, opticalaswellaselectricalpropertieshasbeenstudied.XRDandRamanexaminationsdemonstratethesubstitutionofZnþ2 ions by Inþ3 ions atlowerindiumconcentrations,whileIn2O3 appears asseparatephaseathigherInratios.Thenanowirestransformtonanoflakes then nanoflowers astheInconcentrationincreases.Withregardtotheopticalproperties,thetransparencyincreaseswithincreasingInand decreases thereafter.TheopticalbandgapvaluesincreasewithIncontentreachingitsmaximumvalue(3.28eV)forthesampleof x¼5 at%.The refractive index,extinctioncoefficient andUrbachtailarealsoaffectedbyIndoping.Theelectricalconductivityenhancesatlowerdopinglevel due toformationofthermallyactivateddonorlevels,despitethis,thephaseseparationandphononscatteringarefactorsresponsiblefor conductivity decreaseathigherIncontent. إقراء المزيد