Magnon laser

Abstract

We experimentally demonstrate a magnon laser based on the coherent Bose-Einstein condensate of magnons brought into motion by using a time-dependent spatially inhomogeneous magnetic field. We show that the application of a short field pulse results in the formation of a condensate cloud moving with the constant velocity of 930 m/s for the used parameters of the experiment. The number of magnons building the cloud is not changed during the propagation, which is reminiscent of the magnon superfluidity.