Temperature and frequency dependence of linewidth in BaFe<inf>12</inf>O<inf>19</inf>

Abstract

In order to determine the important magnetic loss mechanisms in the hexagonal ferrite BaFe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">19</inf> , the ferromagnetic resonance linewidth has been measured as a function of temperature and frequency. Measurements were performed over the temperature range of 60° to 300°K and frequency range 52 to 64 GHz, both for pure and for Mn-substituted barium ferrite. Our results indicate that the bulk of the linewidth in high-quality, pure barium ferrite crystals can be attributed to an intrinsic Kasuya-LeCraw scattering process. The same measurements on manganese-substituted barium ferrite (BaFe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11.8</inf> Mn <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">19</inf> ) revealed a somewhat more complicated temperature dependence for the linewidth. The magnetic loss for the Mn-substituted sample is explained as the sum of two separate contributions: a Kasuya-LeCraw scattering loss, and a temperature peak process due to crystal impurities.