Electrical, magnetic and microwave absorption properties of multiferroic NiFe2O4-BaTiO3 nanocomposites

Abstract

Multiferroic nanocomposites of xNiFe2O4/(1-x)BaTiO3 (x = 0, 0.1, 0.2, 0.3, and 0.4) (denoted as NFO-BTO) with the particle size about of 70 nm were prepared by the high energy mechanical milling combined with the thermal annealing methods. The x-ray diffraction patterns show a presence of NiFe2O4 (NFO) and BaTiO3 (BTO) phases. The values of the characteristic parameters of nanocomposites such as the coercive field (E c), the residual polarization (P r), the remanent magnetization (M r), the saturation magnetization (M s), and the coercive force (H c) increase gradually with an increase in NFO concentration. For an applied electric field below 10 kV cm−1, the values P r and E c are found to be 0.004–0.038 μC cm−2 and 0.7–2.0 kV cm−1, corresponding x = 0.1–0.4, respectively. Changes in electrical and magnetic properties of composites depend heavily on the NFO content, which will be studied specifically. Additionally, the ability to absorb microwave at room temperature of a representative sample with x = 0.3 mixed in acrylic paint (denoted as NFO-BTO-AP) in a frequency range of f = 12–18 GHz has also been investigated. It shows a large negative reflection loss (RL) with RL = −39.8 dB occurring at around 16.8 GHz corresponding to the absorptivity of over 99.9% for an absorbing layer with thickness of 5.5 mm. This suggests that NFO-BTO nanocomposites could be considered as a potential material in the field of absorbing and shielding electromagnetic waves.