Preparation and functional characterization of magnetoelectric Ba(Ti1-xFex)O3-x/2 ceramics. Application for a miniaturized resonator antenna

Diluted magnetic oxides attracted a great interest in the last years as materials for spintronics and magnetoelectric devices. We propose in the present paper such a magnetoelectric ceramic system for an application as miniaturized resonator antenna in GHz range. BaTi_1-xFe_xO_3-x/2 (0?≤?x?≤?0.02) polycrystalline ceramics have been produced by solid state reaction. X-ray diffraction analysis and Rietveld refinement have shown that Fe doping of BaTiO₃ lattice produces a transition from tetragonal crystalline symmetry (for x?≤?0.01) to a superposition of tetragonal and hexagonal phases for the compositions x?=?0.015 and 0.02. As result of Fe addition, the Curie temperature of BaTi_1-xFe_xO_3-x/2 ceramics exhibit a shift from 127?°C towards lower values and reaches 85?°C for x?=?0.02. A competition between weak ferromagnetic and antiferromagnetic character as a function of composition and temperature is determined both by the presence of transition metal ion and of the oxygen vacancies. Due to its electromagnetic properties, an optimized composition x?=?0.01 was used for producing a miniaturized antenna which was found to show a frequency dependent S₁₁ response similar to the simulated one.