Resonances involve integer magnons in a magnetism modulated two-dimensional electron gas*

We conduct an experimental study of high-mobility two-dimensional electron gas (2DEG) in GaAs/AlGaAs quantum wells modulated by strong magnetism at an in-plane magnetic field. The modulated magnetic fields on 2DEG are performed via the single stripe and gratings which are made of the heavy rare earth metal on the sample surface. We observe that the complicated ferromagnetic resonances (FMRs) persist until above several tens Kelvins in both the stripe and grating samples, for the FM phase of the magnetic metal exists at above 100 K. The high-order (with integer number j = 1, 2...) FMR can also be observed in the stripe structure via the microwave photovoltaic detection and magnetoresistance under microwave irradiation. It indicates that the transport involves integer magnons. In addition, the resonance features around j = 1/2 are robust in the single-stripe modulated sample, which suggests the spinors in the 1D spin channel.