Improvement of the magnetoelectric response in NiFe2O4-Sr0.5Ba0.5Nb2O6 composites using LiNbO3 as sintering additive

Abstract

Magnetoelectric (NiFe2O4)0.3−(Sr0.5Ba0.5Nb2O6)0.7 composites with addition of LiNbO3 as sintering additive were prepared by a classical mixed-oxide method. XRD patterns of ceramics sintered between 1000 and 1200 °C show the desired Sr0.5Ba0.5Nb2O6 and NiFe2O4 phases. SEM investigations confirm the 0–3 connectivity of the composite ceramics. The addition of 10 and 20 mol% LiNbO3 improves the densification of the composite ceramics and leads to an increase of the size of the Sr0.5Ba0.5Nb2O6 grains. Magnetic measurements show hystereses with low coercivities. Dielectric measurements were carried out depending on temperature and frequency. The samples with the LiNbO3 addition show significantly higher resistivity values (σDC). Magnetoelectric measurements were carried out in dependence of the magnetic DC-field, temperature, and frequency. The maximum magnetoelectric coefficient (αME) rises with the addition of LiNbO3 from 180 to 803 µV Oe−1 cm−1 (@900 Hz). Temperature dependent measurements show a continuously decreasing of αME with lower temperature.