Improving Dielectric And Magnetic Properties Of (Cr, Fe, Ni)-Doped Sic Microwaves Absorbents: A Dft Study

Abstract

In wireless telecoms, EM waves absorbers become important if applied outside special fields like rooms, radar systems, and military application. Composite materials allow convenient use on surfaces, good control over mechanical properties, variation of EM properties with proper selection of matrix material and different inclusions. Wide frequency range, zero external magnetic field, thin absorption layer (required for absorbers) limit FM materials for microwave frequency range. In absorber composites, and FM inclusions reduce impedance mismatches at front interface of absorbers and increase absorption of EM waves (V. B. Bregar, IEEE Transactions on Magnetics (2004) 40, 3). Cr4+ transition metal ions provide a rich set of optically active defect spins in wide bandgap semiconductors, and produce in SiC a spin-1 ground state with a narrow, spectrally isolated, spin-selective, near-telecom optical interface (B. Diler, npj Quantum Inf (2020) 6, 11). Cr4+ are detected by placing the device into a photonic cavity to reduce the excited state lifetime by Purcell enhancement: large fraction of indistinguishable photons in near telecom ZPL would be further enhanced (A. M. Dibos et al., Phys. Rev. Lett. (2018) 120, 243601). A metallic character shown by (Ni, Cr)-codoped 4H–SiC, and a FM order mainly due to Cr impurities, originating from a strong FM coupling due to p-d hybridization interaction, allow us using our alloys in microwave circuits as absorbers. 4H-SiC (P63mc hexagonal structure of a =b =3.081 Å, c = 10.096 Å (B. Song, et al., J. Am. Chem. Soc. 131 (2009) 1376–1377)). To avoid EM pollution caused by electronic and telecom systems, Cr-doped 4H–SiC are used. Cr behaves as donor or acceptor and the dielectric properties of SiC can be changed through n- or p-type doping in the microwave range, where enhanced dielectric loss and improved EM matching are beneficial to get excellent microwave absorption performancee.(Justo JF, MachadoWVM, Assali LVC. Physica B 2006;378:376).