Direct observation of symmetry-specific precession in a ferrimagnet

作者：Warnicke P; Stavitski E; Lee J S; Yang A; Chen Z; Zuo X; Zohar S; Bailey W E; Harris V G; Arena D A^*

来源：Physical Review B, 2015, 92(10): 104402.

DOI：10.1103/PhysRevB.92.104402

Here we demonstrate an experimental observation of GHz-scale spin dynamics resolved to sublattice octahedral (O-h) tetrahedral (T-d) sites in a spinel ferrimagnet, in this case a Mn-ferrite thin film. X-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) are used, in combination with multiplet calculations, to uniquely identify the spectral signature from Mn2+ and Fe-2+,Fe-3+ on O-h and T-d lattice sites. With the sample under rf excitation, the spin alignment of the sublattices is tracked with time-resolved XMCD (TR-XMCD). The spin alignment of the sublattices is mostly antiferromagnetic. The phase difference between the O-h Fe2+ [O-h Fe3+] and T-d Mn2+ sites is 181.2 +/- 3.8 degrees [183.3 degrees +/- 3.7 degrees] at 150 K and 186.6 +/- 2.2 degrees [182.0 degrees +/- 2.2 degrees] at 300 K. Such direct measurement of the dynamic coupling, exchange stiffness, and damping enabled by TR-XMCD across sublattices will be essential for optimizing the development of future-generation microwave devices.

• 出版日期2015-9-1
• 单位东北大学