Enhancement of uniaxial anisotropy constant by introducing oxygen vacancies in Ca-doped YIG

Abstract
Ca‐doped YIG films having composition Y3−x3+ Cax2+ Fe3+5−x Fex4+ O1 2 have been grown with a value of x = 0.25 and thickness 1.15 μm. Upon annealing in saturated FeCl2 solution, oxygen vacancies are introduced, which compensate for Ca2+ ions and reduce Fe4+ ions to Fe3+ ions. The uniaxial anisotropy constant changed from −5.89×103 erg/cm3 to −17.0×103 erg/cm3, which is consistent with a change in the crystal field effects reduction as proposed by Stacy and Rooymans. The exchange stiffness coefficient changed from 3.19×10−7 erg/cm to 3.66×10−7 erg/cm. The exchange stiffness parameter and the anisotropy energy have been studied as a function of temperature and oxygen vacancy concentration.