Controlling and patterning the effective magnetization in Y3Fe5O12 thin films using ion irradiation

We report an approach to controlling the effective magnetization (M-eff), a combination of the saturation magnetization and uniaxial anisotropy, of the ferrimagnet Y3Fe5O12 (YIG) using different species of ions: He+ and Ga+. The effective magnetization can be tuned as a function of the fluence, with He+ providing the largest effect. We quantified the change in effective magnetization through an angular dependence of the ferromagnetic resonance before and after irradiation. Increases in 4 pi M-eff were observed to be as much as 400 G with only a 15% increase in Gilbert damping, alpha (from 8.2e-4 to 9.4e-4). This result was combined with a method for accurate ion pattering, a focused ion beam, providing a mechanism for shaping the magnetic environment with submicron precision. We observe resonance modes localized by ion patterning of micron-sized dots, whose resonances match well with micromagnetic simulations. This technique offers a flexible tool for precision nanoscale control and characterization of the magnetic properties of YIG. (C) 2017 Author(s).