Microwave absorption properties of (1-x)La0.85Ag0.15MnO3/x graphene (x=0, 3, and 5 wt.%) composites

Composite of (1 - x)La0.85Ag0.15MnO3/x graphene (x = 0, 3, and 5 wt.%) and epoxy resin with a ratio of 4:1 were prepared to investigate the influence of the addition of graphene in (1 - x)La0.85Ag0.15MnO3/x graphene on real and imaginary parts of permittivity, permeability, as well as microwave reflection loss (RL), using a vector network analyzer in the 8-18 GHz of the frequency range. It is found that the value of RL is smaller at x = 3 wt.% (-20.74 dB at 14.85 GHz) and 5 wt.% (-14.81 at 16.50 GHz) compared to at x = 0 wt.% (-8.89 dB at 15.90 GHz). The result indicates that microwave absorption properties significantly improved as a result of the addition of graphene. It is suggested that the addition of graphene enhanced the dielectric loss-related mechanism such as interfacial polarization and conduction loss resulting in an improvement of microwave absorption performance for both x = 3 wt.% and x = 5 wt.% samples. It also shows that the observed enhanced microwave absorption properties may also be influenced by the resistivity of the sample as x = 3 wt.% sample exhibits enhanced microwave absorption properties and the lowest resistivity among the studied samples.