Strong magnetic relaxation of tetravalent iron ions in calcium-doped yttrium iron garnet films

Abstract

Ferromagnetic resonance relaxation has been used to study a series of LPE-grown YIG films containing calcium in increasing concentrations. The considerably large linewidths revealed that a high population of Fe4+ ions is allowed to enter the epilayers. Etching techniques and selective heat treatments provided respectively an insight on the Ca-concentration gradients within the films and a means of confirming the identification of the relaxing ions.