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Kumar P.,Electroceramics Research Laboratory | Kumar P.,Thapar University | Singh S.,GVM Girls College | Juneja J.K.,Hindu College | And 2 more authors.
Ferroelectrics, Letters Section | Year: 2010

In the present work, we are reporting the effect of Mn doping on the structural, dielectric and ferroelectric properties of Ba0.80Pb 0.20Ti0.90Zr0.10O3. Samples were prepared by solid state reaction route. X-ray diffraction analysis confirmed the compositions to be single phase. Dielectric properties were studied as a function of temperature and phase transition temperature (Tc) was determined. Ferroelectric behaviour was studied in detail as a function of temperature. Mn doping was found to improve temperature stability of the material.


Rani R.,Electroceramics Research Laboratory | Rani R.,Thapar University | Juneja J.K.,Hindu College | Raina K.K.,Thapar University | Prakash C.,Directorate of ER and IPR
Journal of Ceramic Processing Research | Year: 2012

Piezoelectric-magnetostrictive (magnetoelectric) composites using piezoelectric lead zirconate titanate (PZT) ceramic and magnetostrictive Ni-Zn ferrite (NZF) with compositional formulae (1-x) PbZr 0.65Ti 0.35O 3-x Ni 0.8Zn 0.2Fe 2O 4 with x = 0 to 0.15 in steps of 0.05, were prepared by a conventional solid state route. The presence of individual phases was confirmed using X-ray diffraction. Dielectric properties were studied as a function of temperature and frequency presuming that the interactions between the piezoelectric and magnetostrictive phases may result in various anomalies in the dielectric properties of these composites. To study the ferroelectric properties, P-E hysteresis loops were recorded.


Rani R.,Electroceramics Research Laboratory | Kumar P.,Electroceramics Research Laboratory | Juneja J.K.,Hindu College | Raina K.K.,Thapar University | Prakash C.,Directorate of ER and IPR
Advances in Condensed Matter Physics | Year: 2011

We report studies on dielectric properties of magnetoelectric composites of La-substituted lead zirconate titanate (PLZT) and zinc-doped nickel ferrite (NZF) with compositional formula 0.95 Pb 1-3x/2La xZr 0.65Ti 0.35O 3-0.05 Ni 0.8Zn 0.2Fe 2O 4 (x = 0, 0.01, 0.02, and 0.03). The materials were synthesized by conventional solid state reaction route. The presence of individual phases (PLZT and NZF) was confirmed by using X-ray diffraction technique. Dielectric properties were studied as a function of temperature and frequency. Significant improvement was observed in dielectric properties with addition of La. Copyright © 2011 Rekha Rani et al.


Rani R.,Electroceramics Research Laboratory | Rani R.,Thapar University | Juneja J.K.,Hindu College | Singh S.,GVM Girls College | And 2 more authors.
Ferroelectrics, Letters Section | Year: 2012

Magnetostrictive-piezoelectric (magnetoelectric) composites using magnetostrictive nickel zinc ferrite (NZF) and piezoelectric lead zirconate titanate (PZT) having compositional formula yNi0.8Zn 0.2Fe2O4-(1-y)PbZr0.65Ti 0.35O3 (0 ≤ y ≤ 0.15 in the steps of 0.05) were synthesized by conventional solid state method. Room temperature P-E and M-H hysteresis loops were recorded to study ferroelectric and magnetic properties of composites respectively. Effect of electric poling on values of remanant magnetization (Mr) and saturation magnetization (Ms) was studied for all composite samples (y = 0.05, 0.10 and 0.15) to confirm magnetoelectric (ME) coupling. ME coefficient (dE/dH) was measured as a function of dc magnetic field for all composite samples. Copyright © Taylor & Francis Group, LLC.


Rani R.,Electroceramics Research Laboratory | Rani R.,Thapar University | Juneja J.K.,Hindu College | Singh S.,GVM Girls College | And 2 more authors.
Journal of Magnetism and Magnetic Materials | Year: 2013

Magnetoelectric composites of nickel zinc ferrite (NZF) and La substituted lead zirconate titanate (PLZT) having representative formula 0.1Ni 0.8Zn 0.2Fe 2O 4-0.9Pb 1-3x/2La xZr 0.65Ti 0.35O 3 (x=0, 0.01, 0.02 and 0.03) were synthesized by a conventional solid state route. X-ray diffraction analysis was carried out to confirm the coexistence of individual phases. Scanning electron microscope micrographs were taken for microstructural study of the samples. Dielectric properties were studied as a function of temperature and frequency. To study ferroelectric and magnetic ordering in composite samples, P-E and M-H hysteresis loops were recorded respectively. M-H hysteresis loops were taken for electrically poled and unpoled samples to confirm magnetoelectric coupling between the two phases (NZF and PLZT). La substitution results in significant improvement in dielectric, ferroelectric and piezoelectric properties of composite samples. © 2012 Elsevier B.V. All rights reserved.


Maisnam M.,Manipur University | Phanjoubam S.,Manipur University | Prakash C.,Directorate of ER and IPR
Modern Physics Letters B | Year: 2010

Cd2+ substituted Li-Zn ferrite with compositional formula Li0.4-x/2Zn0.2CdxFe2.4-x/2O 4 with x = 0.02, 0.03 and 0.04 were prepared by the conventional double sintering ceramic technique. XRD technique confirmed the formation of single phase with spinel structure. The substitution causes an increase in the lattice constant, density and DC resistivity, while the Curie temperature and dielectric constant decreases with Cd2+ substitution. The mechanisms involved are discussed. © 2010 World Scientific Publishing Company.


Pathak A.,Indian Institute of Technology Delhi | Chatterjee R.,Indian Institute of Technology Delhi | Prakash C.,Directorate of ER and IPR
Ceramics International | Year: 2010

A modified lead zirconate stannate titanate system (PZST) has been studied for shape memory effect. Addition of magnesium niobate (MN) slows down the dipole relaxation process, leading to increased (∼3-fold improvement) remnant strain in the PZST system (0.99PZST-0.01PMN). Room temperature X-ray diffraction patterns before poling (antiferroelectric (AFE) tetragonal) and after poling (ferroelectric (FE) rhombohedral), clearly demonstrate that the transition to the ferroelectric phase is stable even in the absence of any electric field. A small applied electric field (∼1.7 kV/cm) in the opposite direction was required to bring the sample back to its original shape. Field-induced strain butterfly loops taken at 50 Hz show that the material response time is quite small. © 2010 Elsevier Ltd and Techna Group S.r.l. All rights reserved.


Mahajan S.,Solid State Group | Mahajan S.,University of Delhi | Mahajan S.,Indian Institute of Technology Delhi | Thakur O.P.,Solid State Group | And 2 more authors.
Integrated Ferroelectrics | Year: 2010

Here we are reporting influence of Nd substitution on properties of Zr modified BaTiO3 [(BaZrxTi1-xO3), BZT5)]. The composition Ba1-xNdx (Zr0.05Ti 0.95)O3 (x= 0-0.04) was prepared by conventional solid state reaction route. The sintered sample was characterized for its structural properties by XRD and Raman analysis. The dielectric properties were measured as a function of temperature in the frequency range of 100 Hz to 500KHz. A high value of dielectric constant (∼23,000) is observed at room temperature as compared to undoped BaTiO3 (∼2500). It also observed that the three phase transition temperatures corresponding to pure BZT5 merge with substitution and exhibit a single ferroelectric to paraelectric phase transition. The value of remnant polarization and coercive field at room temperature were obtained from polarization vs electric field loop measurement on unpoled ceramic sample. Copyright © 2010 Taylor & Francis Group, LLC.


Soibam I.,Manipur University | Phanjoubam S.,Manipur University | Prakash C.,Directorate of ER and IPR
Integrated Ferroelectrics | Year: 2010

A series of cobalt substituted lithium zinc ferrites having the compositional formula Li0.4-0.5xZn0.2CoxFe 2.4-0.5xO4, where 0.00 ≤ x ≤ 0.1 in steps of 0.02, was prepared by the citrate precursor method. Structural studies on the prepared samples were carried out by using XRD and SEM measurements. Spinel phase structure of the samples was confirmed by XRD. From the XRD data the lattice parameter and the theoretical density were calculated. The experimental density was also determined using the Archimedes principle. Lattice parameter was observed to increase with increasing Co2+ ion concentration. The densification in both the cases, theoretical and experimental, shows an increase with composition. SEM studies carried out show that average grain diameter are in the range of 300 nm-650 nm and a fall is observed with increasing Co 2+ ion content. The investigation on initial permeability as a function of composition and frequency were also undertaken. It is seen that there is decrease in the value of initial permeability with addition of Co content. The initial permeability and permeability loss show dispersion with frequency. Possible mechanisms contributing to the above processes are discussed. Copyright © Taylor & Francis Group, LLC.


Maisnam M.,Manipur University | Phanjoubam S.,Manipur University | Kumar P.,GVM Girls College | Juneja J.K.,Hindu College | And 2 more authors.
Integrated Ferroelectrics | Year: 2010

Substituted Li-ferrites are attractive materials for research due to their important properties like high Curie temperature leading to high thermal stability, high and wide range of saturation magnetization, low stress sensitivity of remanence and they are very good dielectric materials. The properties are very sensitive to the type and amount of substituents, method of preparation and sintering conditions. Attempts to minimize loss of lithia and oxygen during sintering by adopting various processing method, which otherwise is very difficult to control technologically by conventional method, has been a continuous efforts for the researchers. The present paper reports the improvements that arise in the properties of Li-Mn-Ti ferrite by using novel microwave (MW) processing technique. Mn4+ and Ti4+ substituted Li-ferrites having the compositional formula Li 0.60Mn0.1Ti0.1Fe2.20O4 were prepared by both the conventional and microwave techniques. XRD confirmed the formation of single phase with spinel structures in both the samples. Dielectric properties were studied as a function of temperature. Dielectric properties of MW processed sample were found to be more stable with temperature. Significant improvement in the d. c. resistivity was observed in theMWsintered sample over the conventional sintered sample. The possiblemechanisms involved are discussed. Copyright © 2010 Taylor & Francis Group, LLC.

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