Complex magnetic permeability and dielectric permittivity of micro- and nano-sized powdered barium (BaFe12O19) and strontium (SrFe12O19) hexaferrites have been studied in a broadband millimeter wave frequency range (30-120 GHz). Transmittance measurements have been performed using a free space quasi-optical millimeter wave spectrometer, equipped with a set of high power backward wave oscillators. Real and imaginary parts of dielectric permittivity for both types of micro- and nanoferrites have been calculated using analysis of recorded high precision transmittance spectra. Frequency dependences of the magnetic permeability have been obtained from Schlömann’s equation for partially magnetized ferrites. These materials show promise as tunable millimeter wave absorber, based on their size-dependent absorption.
Revised: February 24, 2012 |
Published: February 22, 2012
Citation
Korolev K.A., J.S. McCloy, and M.N. Afsar. 2012.Ferromagnetic Resonance of Micro- and Nano-sized Hexagonal Ferrite Powders at Millimeter Waves.Journal of Applied Physics 111, no. 7:Article No. 07E113.PNNL-SA-82678.