Multiferroic composites in nano-microscale with non-solid solution by Co-ferrite and (K_(0.5)Na_(0.5))NbO_3-based ferroelectric matrix

摘要

A new kind of lead-free multiferroic magnetoelectric composites was successfully prepared by incorporating the dispersed CoFe_2O_4 (CFO) ferromagnetic nanoparticles into (K_(0.5)Na_(0.5))NbO_3-LiSbO_3 (KNN-LS5.2) ferroelectric micromatrix. The dependence of dielectric properties and DC magnetization on CFO phase content was systemically studied. The results show that the dielectric constant decreases with increasing CFO phase content at higher frequencies while the loss tangent and the magnetic moment increase with it. Variation of dielectric constant and dielectric loss with frequency also showed dispersion in the low frequency range, and the values of (epsilon_(r max)- epsilon_(r min))/epsilon_(r max) increase with the increase in ferrite CFO content. The value of H_(bias) corresponding to alpha_E~(max) almost linearly increases with the increase in ferrite CFO content in composites. We can conclude that the main reasons of dispersion were correlative with the heterogeneous conduction in the multiphase structure of the composites. A maximum magnetoelectric voltage coefficient of 15.01 mV cm~(-1) Oe~(-1) was observed from the composites with 40 mol percent CFO at 1 kHz, which was a very high value in the lead-free magnetoelectric composite system for the potential use on actuators and sensors, etc.