Microwave induced magnetic decrystallization

A number of crystalline materials in powder form containing magnetic ions have been decrystallized by exposing them to a 2.45 GHz single mode, quasi-pure magnetic field. Irradiations were carried out by placing samples at the specific location in a microwave cavity tuned to the TE₁₀₃ mode where the magnetic field is maximized and the electric field is minimized. After irradiation, the samples sintered but retained their shape (there was no evidence of macroscopic flow); however, XRD and Raman analysis indicated a complete loss of crystallinity. These observations raise several questions: How is electromagnetic energy absorbed in this process? How is it stored? How is decrystallization induced by the microwave magnetic field? This paper presents our current understanding of this remarkable phenomenon.