Yang's Group

The spin waves are a continuous change of local magnetic states above the lowest lying energy in a magnetic medium. They interact with a spin angular momentum which has a spin transfer torque. Such an interaction can causes the amplification and Doppler shift of spin waves. Based on this property, we can develop the spin wave devices for the practical applications.

Recently, the spin waves have a considerable interest because they will give us the fundamental understanding of spin dynamics. Therefore much effort has been exerted to reveal the spin wave properties such as a spectrum, linearity, confinement and so on. With the spin-transfer torque (STT) we can amplify the spin wave amplitude. However, the effect of STT on the spin wave amplification has not yet been investigated experimentally. When spin waves are propagating through two separate sources, they will interfere constructively or destructively in a magnetic film showing distinct interference patterns, so that we can confirm the wavy properties of spin wave. Magnetostatic spin waves change their phase as they pass through domain walls. The interference of merging waves depends on the domain walls. A controlled manipulation of spin wave phases could be the first step towards nano-scaled ferromagnetic devices performing logical operations based on spin wave propagation.