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In the present article, a brief introduction about multiferroic composites is provided. Recent advancement in the field of multiferroic composites is discussed by classifying these in bulk composit...

In this paper, effect of addition of nano-particles of Nickel zinc ferrite on structural, microstructural, dielectric properties of multiferroic composite with compositional formula (x) Ni0.6Zn0.4F...

In this work, multiferroic composite has been prepared using nickel zinc ferrite as ferromagnetic phase and barium strontium titanate as ferroelectric phase. Composite samples were characterized fo...

In this paper, effect of Dy3+ substitution on structural, microstructural, dielectric, ferroelectric and piezoelectric properties of barium titanate has been studied. Results of density measurement indicates that substitution of Dy3+ results in increase in density of BT. Grain size increases significantly with the substitution of Dy3+. Dy3+ substituted BT sample possess higher dielectric constant, better ferroelectric properties but weak piezoelectric properties.

Effect of substitution of Sm3+ on various properties of barium titanate has been studied. Barium titanate (BT) and its Sm3+ substituted derivative has been synthesized using solid state reaction me...

Effect of substitution of rare earth ions (Dy3+, Gd3+ and Sm3+) on various properties of Ba0.95Sr0.05TiO3 (BST) i.e. the composition Ba0.95−1.5xSr0.05RxTiO3 (where x = 0.00, 0.01, 0.02, 0.03 and R are rare earths Dy, Gd, Sm) and that of their multiferroic composite with Ni0.8Co0.2Fe2O4 (NCF) has been studied. Shifting of peaks corresponding to different compositions in the X-ray diffraction pattern confirmed the substitution of rare earth ions at both Ba2+ and Ti4+ sites in BST. It is clear from scanning electron microscopy (SEM) images that rare earth substitution in BST increases its grain size in both pure and composite samples. Substitution of rare earth ions results in increase in value of dielectric constant of pure and composite samples. Sm substitution in BST significantly decreases its Curie temperature. Dy substituted pure and composite samples possess superior ferroelectric properties as confirmed by polarization vs electric field (P–E) loops. Composite samples containing Dy, Gd and Sm substituted BST as ferroelectric phase possess lower values of remanent and saturation magnetizations in comparison to composite sample containing pure BST as ferroelectric phase (BSTC). Rare earth substituted composite samples possess higher value of magnetoelectric coefficient as compared to that for BSTC.

Multiferroic composites have been prepared by submerging of barium strontium titanate (Ba0.95Sr0.05TiO3) (BST) pellets (sintered at different temperatures) in nickel cobalt ferrite (Ni0.8Co0.2Fe2O4) (NCF) Sol followed by sintering. This method resulted into uniform distribution of small amount of NCF nanoparticles in BST matrix. The presence of NCF within BST pellets has been confirmed by magnetization versus magnetic field loops and energy dispersive X-ray spectroscopy (EDS) measurements. Smaller content of NCF in composite samples prepared from submerging method significantly affected dielectric, piezoelectric, and ferroelectric properties. Magnetodielectric effect in composite samples confirmed the presence of magnetoelectric coupling.

Multiferroic particulate composites comprising BaTiO 3 as ferroelectric phase and CoFe 1.8 Zn 0.2 O 4 as ferrite phase with the formula (1− x ) BaTiO 3 –( x ) CoFe 1.8 Zn 0.2 O 4 (where x =10, 20, 30 and 40 wt%) are fabricated by the solid state reaction method. To check the phase purity and structure formation, X-ray diffraction (XRD) technique has been used. XRD patterns confirm the formation of the individual phases and the composites. Using scanning electron microscopy (SEM), the morphology of the composites is studied and reveals an increase in grain size with ferrite content. In addition, significant effect of ferrite content on the dielectric, electric and magnetic properties of the composites has also been observed. Variation of dielectric constant ( e ׳) and loss tangent (tan δ ) with temperature (up to 400 °C) and frequency (20 Hz–1 MHz) have been investigated. Dielectric constant is found to increase as ferrite fraction increases with the appearance of two peaks, one in the lower temperature region and other in the higher temperature region. Peak observed in the low temperature range (120 °C–150 °C) is ascribed to ferroelectric to paraelectric phase transition of the BaTiO 3 phase. The increase in dielectric constant can be attributed to the space charge effect and the hopping conduction mechanism. Besides this, the variation of loss tangent (tan δ ) with temperature of the composites exhibits loss peaks. With increasing frequency, all the composites show usual dielectric dispersion. AC conductivity of the composites has been studied as a function of frequency and temperature to understand the conduction mechanism. The observed behavior of the conductivity can be interpreted using a jump relaxation model (JRM). Polarization ( P ) vs. Electric field ( E ) and Magnetization( M ) vs. Magnetic field ( H ) loops are measured at room temperature which demonstrates that all the composites exhibit simultaneously good ferroelectric and ferromagnetic properties.

In this paper, effect of addition of Ni 0.8 Co 0.2 Fe 2 O 4 (NCF), prepared by three different methods namely solid state reaction method, sol–gel and co-precipitation, has been studied on microstructural, magnetic, dielectric, ferroelectric and magnetoelectric properties of multiferroic composite system 0.95 Ba 0.95 Sr 0.05 TiO 3 –0.05 Ni 0.8 Co 0.2 Fe 2 O 4 . Ba 0.95 Sr 0.05 TiO 3 (BST) has been prepared by solid state reaction method. Titular representation of NCF samples prepared by sol–gel, co-precipitation, solid state reaction method is N–SG, N–CP, N–SS respectively and that of corresponding magnetoelectric composite is C–SG, C–CP, C–SS. X–ray diffraction analysis of the composite samples (C–SG, C–SS, C–CP) indicated the presence of both NCF and BST phases. Rietveld analysis of XRD pattern further confirmed the proper phase formation in the composite samples. Sol–gel and co-precipitation processes result in finer NCF particles as confirmed by Transmission electron microscopy (TEM). Sample N–SG possesses uniform particle size and shape. Magnetization versus magnetic field ( M – H ) loops of samples C–SS and C–CP possess respectively highest value of remanant magnetization and magnetic coercive field. Dielectric properties of BST, NCF and composite samples have been measured in the frequency range of 20 Hz–1 MHz and temperature range of 50–170 °C. The composite sample C–CP results in highest value of dielectric constant in comparison to samples C–SS and C–SG. Polarization versus electric field (P – E) measurements pointed that composite sample C–SG possesses highest value of remanant and saturation polarization and C–SS possesses lowest value of coercive electric field. The composite sample C–SS possesses highest value of magnetoelectric coefficient.

In this paper, structural, microstructural, dielectric, magnetic, ferroelectric, and magnetoelectric properties of a multiferroic composite with compositional formula (x) Ni0.8Co0.2Fe2O4+(1−x) Ba0.95Sr0.05TiO3 (where x=0.0, 0.02, 0.04, 0.06, 0.08, 0.10, 1.00) has been studied. Nanoparticles of Ni0.8Co0.2Fe2O4 ferrite have been prepared by the sol–gel method. Ba0.95Sr0.05TiO3 ceramic, synthesized by solid state reaction, has particle size in the micrometer range. X-ray analysis along with Rietveld refinement confirmed the formation of cubic spinel and perovskite structure for ferrite and ferroelectric phases, respectively. Transmission Electron Microscopy (TEM) analysis showed that Ni0.8Co0.2Fe2O4 particles have particle size in 25–60 nm range. Samples were characterized for the microstructural analysis by Scanning Electron Microscopy (SEM). Quantitative elemental analysis of the composite samples was carried out by Energy Dispersive X-ray Spectroscopy (EDS). Dielectric properties were studied as a function of frequency in the range 20 Hz–1 MHz for pure and composite samples. AC conductivity measurements suggested that small polaron hopping is the dominant conduction mechanism in the composites. Polarization vs. Electric field (P–E) and Magnetization vs. Magnetic field (M–H) hysteresis loop measurements respectively, confirmed good ferroelectric and ferromagnetic behavior of the composites. Complex impedance spectroscopy measurements at different temperatures confirmed the semiconducting nature of the composites. Magnetoelectric coupling between ferrite and ferroelectric phases was confirmed by measuring M–H hysteresis loops of electrically poled and unpoled samples.

MANETs do not have any fixed infrastructure and consist of wireless mobile nodes that perform various data communication tasks. Mobile ad hoc networks (MANETs) are collection of distributed nodes which communicate using multi-hop wireless links with frequent node mobility. The frequent mobility of nodes leads network partition and futile communication. So, there need an interconnection technique that should guarantee network connectivity, efficient routing and maintain network performance in MANET. Clustering has become an important approach to manage MANETs. This paper proposed Weighted Cluster Based Distributed Spanning Tree (WCBDST) routing technique to form better MANETs interconnections. WCBDST is an interconnection technique in which nodes of MANETs are made to form a forest of spanning tree with root node as cluster head in a distributed fashion which improved routing, network connectivity and maintains network performances.

Multiferroic composites (1-x) Ba0.95Sr0.05TiO3 + (x) Ni0.8Co0.2Fe2O4 (where x = 0.1, 0.2, 0.3, 0.4) has been prepared by solid state reaction method. X-ray diffraction analysis of the composite samples confirmed the presence of both barium strontium titanate (BST) and nickel cobalt ferrite (NCF) phases. FESEM images indicated the well dispersion of NCF grains among BST grains. Dielectric constant and loss of the composite samples decreases with increase in frequency following Maxwell-Wagner relaxation mechanism. Composite sample with highest ferrite content possesses highest values of remanent and saturation magnetization.