Interaction of subthermal magnons and phonons and their role for the transverse Seebeck effect

• Applicant: Professor Sergej O. Demokritov, Ph.D.
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 257847002

We plan to investigate interaction between subthermal magnons and phonons in the gigahertz frequency interval by applying a gradient of either magnon or phonon temperatures with targeting the understanding of their role in the transverse spin Seebeck effect (TSSE). Particular attention will be paid to magnons in YIG films with energies close to the minimum of their spectrum, whereas both incoherent magnons and Bose-Einstein condensates (BEC) will be addressed. Properties of these magnons in thermal gradient as well as under influence of acoustic spin pumping at gigahertz frequencies will be studied. Time-resolved studies of TSSE will be performed in two model systems: YIG/Pt and NiFe/Pt, whereas gradients of magnon temperature will be created using microwave pumping or spin-current injections, correspondingly. Taking advantage of a difference between magnon-magnon and magnon-phonon times, time-resolved measurements will clarify the role of subthermal magnons in the effect.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1538: Spin Caloric Transport (SpinCaT)