International Conference on Benchmarks in Engineering Science and Technology ICBEST 2012 Proceedings published by International Journal of Computer Applications® (IJCA) 6 Magnetoelectric Effect in Substituted Zinc Ferrite Lead Titanate Particulate Compsites R. R. Kherani, K. G. Rewatkar, S. D. Chachere, A. S. Kakde Department of Physics, Shivaji Science College, Rajura, Dist: Chandrapur Department of Physics, Dr. Ambedkar College, Deeksha Bhoomi, Nagpur Department of Physics, Shri. Dnyanaesh Mahavidyalaya, Nawargaon, Dist. Chandrapur ABSTRACT Magnetoelectric composites containing PbTiO 3 ZnFeCoO 4 phases have been prepared by standard ceramic technique. The structure and morphology of the composites were examined by means of X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The XRD result showed that the composites consist of spinel ZnFeCoO 4 phase and pervoskite PbTiO 3 phase annealing at temperature 750 o C. The variation in dielectric constant with the temperature and low frequency it shows dispersion in certain frequency. The dielectric properties are strongly influenced by interface phenomenon (Maxwell Wagner) due to the local electrical inhomogeneity. The peak value of dielectric decreases with increase in temperature. Conductivity, Susceptibility and permeability have been found to vary with temperature and concentration of ferrite phase due to increase in crystalline size. The static value of magnetoelectric conversion factor (dE/dx) was measured as function of applied magnetic field. The coexistence of inductive and capacitive natures in the composites favours size rsduction and designation simplification in many passive electronic devices such as integrated filters and microwave absorbers. Keywords: composites, Dielectric properties, magnetic properties, magnetoelectirc effect, magnetostrictive etc. 1. INTRODUCTION The magnetoelectric composites with piezoelectric and magnetostrictive materials are of interest as transducers, which transform changes in a magnetic field into electric voltage and vice versa [1-3]. It can be used as a magnetic field sensor for an alternative tool of the Hall sensor for magnetic field measurement, or as an electric current measurement. The unidirectional solidification helps in the decomposition of the eutectic liquid composition into alternate layer of the constituent phase: a piezoelectric pervoskite phase and a piezomagnetic spinel phase. Although the measurement voltage coefficient (dE/dH = 130 mV/cm. Oe) [4] was superior to single phase materials such as Cr 2 O 3 solidification process required high temperature and a critical control over the composition especially when one of the components (oxygen) was gas, and the unexpected third phase appeared in the composites [5]. In 1978, they reported on sintered magnetoelectric composites of BaTiO 3 and Ni(Co,Mn)Fe 2 O 4 with excess TiO2 in terms of the particle size effect, the cooling rate, and the mole ratios of both the phases [5]. They reported a maximum value of the magnetoelectric voltage coefficient of 80 mV/cm. Oe in sintered magnetoelectric composites. However, this value was still lower than in situ composites, and it required special poling process for high magnetoelectric effect. Sintered magnetoelectric composites have many advantages compared to in situ composites [5]. The sintered composites are much easier and cheaper in fabrication than in situ composites. Moreover, molar ratio of phases, grain size of each phase, and sintering temperature are easily controllable. These are some important issues in fabricating the sintered magnetoelectric particulate composites. First, no chemical reaction should occur between the piezoelectric and magnetostrictive materials during the sintering process. The chemical reaction may reduce the piezoelectric or magnetostrictive properties of each phase. Second, the resistivity of magnetostrictive phase should be as high as possible. If the resistivity of magnetostrictive is low, the electric poling becomes very difficult due to leakage current. Also, the leakage current reduces the magnetoelectric properties of the composites. When the ferrite particles make connected chains, the electric resistivity of the composites is reduced significantly, because of low resistivity of ferrite. Therefore, good dispersion of the ferrite particles in the matrix is highly required in order to sustain sufficient electric resistivity of the composite. Third, mechanical defects such as pores in the interface between two phases should not exist in the composite for good mechanical coupling. 2. EXPERIMENTAL Preparation of Ferrite phase ZnFeCoO4 (ZFC) The ferrite phase was prepared by using analytical grade ZnO, Fe 2 O 3 and Co 2 O 3 in stoichiometric proportions of these oxides were weighed and mixed thoroughly. These constituents were finely powdered in agate bowls with acetone medium for 10 hrs. The sherry was dried, and dried powders were loosely packed in the form of pellets. These pellets were calcinated in a closed furnace of 1000 o C for 10 hrs with 5 o C/min heating/cooling rate with intermediate grinding. After calcinations, these pellets were crushed powdered to obtain fine particle size. Preparation of Ferroelectric Phase (PTO) The ferroelectric phase PbTiO 3 was prepared from the starting materials as the analytical grade PbO and TiO 2 as starting materials. These constituents weighed in stoichiometric proportion and mixed thoroughly. These powdered were mixed in agate mortor for 10 hrs in an acetone medium. Later pellets were formed and then calcinated at 600 o C for 3 hrs. after calcination these pellets were crushed and finely powdered with agate mortor. These fine powders thus obtained were employed for the preparation of the ME composites. Preparation of Particulate Composites The ferromagnetic and ferroelectric phase PbTiO 3 (PTO) and ZnFeCoO 4 (ZFC) powders were mixed in stoichiometric