@article{13479, author = {Sinéad Ryan and Anya Grafov and Na Li and Hans Nembach and Justin Shaw and Hari Bhandari and Tika Kafle and Richa Sapkota and Henry Kapteyn and Nirmal Ghimire and Margaret Murnane}, title = {Uncovering the Timescales of Spin Reorientation in TbMn6Sn6}, abstract = {

TbMn6Sn6 is a ferrimagnetic material which exhibits a highly unusual phase transition near room temperature where spins remain collinear while the total magnetic moment rotates from out-of-plane to in-plane. The mechanisms underlying this phenomenon have been studied in the quasi-static limit and the reorientation has been attributed to the competing anisotropies of Tb and Mn, whose magnetic moments have very different temperature dependencies. In this work, we present the first measurement of the spin-reorientation transition in TbMn6Sn6. By probing very small signals with the transverse magneto-optical Kerr effect (TMOKE) at the Mn M-edge, we show that the re-orientation timescale spans from 12 ps to 24 ps, depending on the laser excitation fluence. We then verify these data with a simple model of spin precession with a temperature-dependent magnetocrystalline anisotropy field to show that the spin reorientation timescale is consistent with the reorientation being driven by very large anisotropies energies on approximately ≈ meV scales. Promisingly, the model predicts a possibility of 180o reorientation of the out-of-plane moment over a range of excitation fluences. This could facilitate optically controlled magnetization switching between very stable ground states, which could have useful applications in spintronics or data storage.

}, year = {2024}, journal = {Submitted}, url = {https://arxiv.org/abs/2407.18894}, }