Qualitative Analysis of Magnetic Moment in BaxTiO3 - Ni xFe3- xO4 Nanocomposite Synthesized by Novel low Temperature Technique

A novel low temperature preparation technique (<500ºC) is employed for synthesizing nanoscale Barium Titanate -Nickel ferrite composites, where the particle size is controllable. Two different ratios of hard and soft site composites (BTO-NFO 80:20, BTO-NFO 70:30) are synthesized and characterized to study their unique structural, morphological and magnetic properties. The structural refinement studies using XRD data showed 43 % of hard phase (anorthic structure) and 57% of soft phase (Cubic Structure) for BTO-NFO 80:20 and similarly 76% of hard phase and 24% of soft phase in the BTO-NFO 70:30 composite respectively. The SEM and EDAX are used to identify smaller particles of 10 nm using histogram and their sample purity. The VSM analysis at room temperature shows superparamagnetic behavior within the soft ferro magnet with maximum retentivity 2.39 emu/g and saturation magnetization, 10.71 emu/g stating that the composites can be used for various biological applications like drug delivery, hyperthermia, MRI, etc. The ratio Mr/Ms is much less than 0.5, which states that multidomain grains or single domains are formed and the particle interaction is by magneto-static interaction confirming its superparamagnetic nature.

Enhancement of the Magnetoelectric Effect in PZT-Ni Ferrite Composites Using Post Sintering Thermal Treatment

In this chapter, the piezoelectric and magnetoelectric properties of Pb (Zr0.52T0.48)O3–X NiFe1.9Mn0.1O4 (PZT-NFM, where X ranges from 3 to 10%) were investigated along with SEM and TEM analysis. Post sintering thermal treatment (annealing and aging) was introduced to enhance the piezoelectric and magnetoelectric property of the composites. The density was found around 7.6–7.8 gm/cc. The piezoelectric constant d33 and the voltage constant were found to be decreased with increasing magnetic particle from 3–10%. Experimental results indicated that the magnetoelectric voltage coefficient (dE/dH) increases with increasing percentage of Nickel Ferrite (~35 for 3% NF to 140 mV/Oe. cm for 10% NF at 1125°C). The samples, which were annealed and aged after sintering show as high as 50% (140 to 220 mV/cm Oe) increase in dE/dH coefficient. This is due to the increase in resistivity due to better homogeneity. The H-M curve of the composite powders show that the PZT-NFM is a ferromagnetic material as well. The SEM investigation shows very compact structure with average grain size around 150 nm and some areas of the NF rich phase. The X-ray mapping shows that the NF is distributed in the big grains of the matrix and after annealing it homogenizes.