Effect of aluminium substitution on low energy electrodynamics of barium-lead M-type hexagonal ferrites
Ahmed, Asmaa, Liudmila Alyabyeva, Victor Torgashev, Anatoly S. Prokhorov, Denis Vinnik, Martin Dressel, and Boris Gorshunov. “Effect of aluminium substitution on low energy electrodynamics of barium-lead M-type hexagonal ferrites.” In Journal of Physics: Conference Series, vol. 1389, no. 1, p. 012044. IOP Publishing, 2019.
We present the first detailed study of the terahertz-infrared dielectric response of single crystalline lead-substituted M-type barium hexaferrites doped with Al3+. The broadband spectra of complex dielectric permittivity ε*(ν)=ε'(ν)+iε”(ν) of Ba0.8Pb0.2AlxFe12-xO19 with concentrations of the dopant x(Al)=1.2, 3, 3.3 are obtained for two principle polarizations using Fourier-transform infrared spectroscopy and terahertz time-domain spectroscopy in the temperature range from 4 to 300 K and at frequencies from 10 cm-1 up to 8000 cm-1 . We observe a rich set of excitations and assign them to the electronic transitions within the ground state 5E of the 4-fold coordinated divalent iron and to phonon resonances. Effect of Al3+ cation substitution on low energy (terahertz) dielectric response and infrared phonon spectra of barium-lead M-type hexaferrites is analysed and discussed.