Lightweight SrM/CCTO/rGO nanocomposites for optoelectronics and K_u band microwave absorption

In this research, nanocomposites comprising M-type strontium hexaferrites (SrM) SrFe_12−xCs_xO₁₉ (x = 0.0, 0.05, 0.10), calcium copper titanate (CCTO) CaCu₃Ti_4−yAl_yO₁₂ (y = 0.0, 0.1, 0.2) and reduced graphene oxide (rGO) have been prepared. XRD patterns shows the presence of single phase nanocrystalline SrM and CCTO which is further supported by Raman spectroscopy and FTIR analysis. The presence of secondary phase such as α-Fe₂O₃, CaTiO₃, and CuO has not been observed. Characteristics absorption bands of Cs-substituted SrM and Al-substituted CCTO were observed at 446, 551 and 605 cm⁻¹, these peaks gives the idea of the formation of SrM and CCTO phase. The D and G bands of GO were observed at 1358 and 1604 cm⁻¹ respectively, while that of the rGO were respectively observed at 1351 and 1595 cm⁻¹. FESEM micrograph show the incorporated SrM nanoparticles, CCTO nanoparticles and rGO sheets, reduction in surface energy and magnetic dipolar interaction prompt the SrM nanoparticles to surround the CCTO nanoparticles and decorate the surface of the rGO sheets. The non-magnetic CCTO phase in the nanocomposites causes the tuning of the magnetic properties. The band gap obtained from UV–vis NIR spectroscopy is within the range of UV-blue LED application. The sample SCR3 shows a maximum reflection loss of − 16.0 dB at 18.0 GHz and matching thickness of 2 mm. The obtained reflection loss is attributed to multiple absorption mechanism as a result of improved impedance matching between the dielectric and magnetic loss absorbents.