• Maricic, Aleksa
• Stojanovic, Nemanja
• Kalezic-Glisovic, Aleksandra
• Janicijevic, Aco

Abstract

<jats:p>Multiferroic systems are attractive to the researches worldwide due todiversity of existing applications, as well as possible novel ones. In orderto contribute to understanding of the processes that take place within thestructure of such a system, we subjected it to mechanochemical activationand thermal treatment. Powdery mixtures of iron and barium titanate in amass ratio of 30% Fe and 70% BaTiO3 were activated in a planetary ball millfor time duration of 30 to 300 min and subsequently sintered at 1200?C inthe atmosphere of air. During the activation the system undergoes structuralphase transitions, whereby the content of iron and its oxides changes. Thehighest Fe content was observed in the sample activated for 270 min, withlocal maxima in crystallite size and microstrain values and a minimum indislocation density. The complex dielectric permittivity changes in theapplied radio frequency field, rangingfrom 176.9 pF/m in thesample activatedfor 90 min to 918.1 pF/m in the sample activated for 180 min. As thefrequency of the field increases, an exponential decrease in the magneticwith a simultaneous increase in the electrical energy losses is noticeable.The system exhibits ferromagnetic resonance, whereby longer activation inthe mill shifts the resonant frequency to higher values. Negative electricalresistance was observed in all analyzed samples. The activation time changesboth the demagnetization temperature and the Curie temperature of thesamples undergoing heating and cooling cycles in the external permanentmagnetic field. Curie temperature is the highest in the sample activated for240 min. Thermal treatment increases the initial magnetization of allsamples, with the most pronounced increase of ~95% in the sample activatedfor 300 min.</jats:p>

Topics

• density
• impedance spectroscopy
• iron
• activation
• magnetization
• Curie temperature
• Barium