Microwave absorption characteristics of Co~(2+) and W~(4+) substituted M-type Ba_(0.5)Sr_(0.5)Co_xW_xFe_(12-2x)O_(19) hexagonal ferrites

摘要

The Co~(2+) and W~(4+) ions substituted M-type hexagonal ferrites, with chemical compositional formula Ba_(0.5)Sr_(0.5)Co_xW_xFe_(12-2x)O_(19) (x = 0.0, 0.2, 0.8 and 1.0), were synthesized by a standard ceramic method. The phase evolution of the compositions was characterized by using an X-ray diffraction. The microwave absorption of compositions has been investigated as a function of frequency, substitution and thickness from 8.2 to 12.4 GHz by an absorber testing device method. The microwave absorption has been evaluated using the standard model of quarter wavelength mechanism and an impedance matching mechanism. The microwave absorption is enhanced in x = 0.0 and 0.2, with former owes 97.0 % absorbed power at 11.22 GHz and 2.4 mm respectively. Compositions x = 0.0, 0.2 and 0.8 exhibit -10 dB absorption bandwidth of 500 MHz while x = 1.0 owes 330 and 340 MHz.