FERRIMAGNETIC RELAXATIONS IN YIG VERSUS FREQUENCY AND TEMPERATURE

Systematic wideband DELTA H equals f ( omega , T) measurements are reported on polycrystalline YIG, between 1 and 18 GHz and between minus 100 and plus 300C. This technique is supposed to allow the separation of the anisotropy and porosity induced contributions in narrow linewidth ferrites. Present data indicate that the microwave losses in ultra-low loss Ca-V-In or Gd-Al-Co substituted YIG are not completely resolvable in terms of these two known processes. The influence of other processes, such as magnetostriction relaxation and surface roughness contributions, appear to be negligible in the case of pure YIG.