Electrical, magnetic and microwave absorption properties of multiferroic NiFe 2 O 4 -BaTiO 3 nanocomposites

Multiferroic nanocomposites of x NiFe 2 O 4 /(1- x )BaTiO 3 ( 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 NiFe 2 O 4 (NFO) and BaTiO 3 (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 μ C 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.