The magnetization dynamics of yttrium iron garnet (Y3Fe5O12, YIG) are key to the operation of spintronic and microwave devices. Here, we report a pathway to manipulate the frequency, damping, and absorption of YIG thin films via interface coupling. The growth on YIG of PtMn, a metallic antiferromagnet, leads to a non-linear resonant frequency vs out-of-plane field dependence and an increased linewidth at low fields. In gadolinium iron garnet/YIG film bilayers, the two films couple antiferromagnetically at low temperatures and there is a strong damping of the magnetization dynamics that is further enhanced at the spin-flop field, suppressing the ferromagnetic resonance signal. When combining both GdIG and PtMn interfaces, we can tune the exponent in the frequency vs field dependence and achieve an almost complete quenching of the magnetization dynamics over a range of fields/frequencies due to non-collinear magnetic order. These effects offer a means to tune and suppress magnetization dynamics for frequency filters, magnonics, spin pumping, and other applications.
Céspedes et al. (Mon,) studied this question.