Ferromagnetic resonance heating of Fe and Fe_3O_4 by 5.8GHz microwave irradiation

摘要

Compressed Fe_3O_4 powder and Fe sheet were pre-heated to various temperatures higher than 300 °C in a microwave magnetic field (h~(rf)). Then an external static magnetic field (H~(ext)) was imposed perpendicularly to h~(rf) and the temperature increased (ΔT: temperature difference from the pre-heated temperature, ΔT _(max): ～200 °C (Fe), ～50 °C(Fe_3O _4)). It had a peak at almost the same H~(ext) during ascent and descent of H~(ext) because of ferromagnetic resonance (FMR). In fact, ΔT became smaller as the preheating temperature was raised to approach the Curie temperature, and H~(ext) corresponding to the temperature peak shifted higher. This report provides FMR heating data under various conditions with quantitative discussion and proposes application of a new heat treatment to materials.