Fig. 4: Time-resolved BLS measurements on the BFO/LSMO heterostructure.

a Sketch of the time-resolved BLS setup and the SEM image of the investigated sample. Probing positions P1 and P2 are depicted in the SEM image with a separation distance \(d=5\,{{\upmu }}{{{{{\rm{m}}}}}}\). The measurement is conducted at 100 mT with the external field applied 48° to the [110] crystal direction of LSMO. b A microwave pulse with the frequency of 7.5 GHz is injected into the NSL antenna. Rising and falling edges are observed at P1 (black line) and P2 (red line) by time-resolved BLS. The blue ellipses mark the slow magnon mode with a time delay \(\Delta t^{\prime}\). c A rising in BLS intensity is first observed in P1 which is close to the NSL antenna, and the rising edge arrives at P2 with a time delay \(\Delta t\). d After the microwave pulse, the falling of the BLS intensity is first observed in P1 and then arrives at P2 with the time delay \(\Delta t\).