Uncovering the Timescales of Spin Reorientation in TbMn6Sn6

Published

July 26, 2024

Author(s)

Sinead Ryan, Anya Grafov, Na Li, Hans Nembach, Justin Shaw, Hari Bhandari, Tika Kafle, Richa Sapkota, Henry Kapteyn, Nirmal Ghimire, Margaret Murnane

Abstract

TbMn6Sn¬6 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 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 TMOKE signals at the Mn M-edge, we show that the re-orientation timescale spans from 12 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 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.

Citation

(potentially a different journal, still TBD)

Pub Type

Journals

Keywords

magnetism, ultrafast, magnetization dynamics

Citation

Ryan, S. , Grafov, A. , Li, N. , Nembach, H. , Shaw, J. , Bhandari, H. , Kafle, T. , Sapkota, R. , Kapteyn, H. , Ghimire, N. and Murnane, M. (2024), Uncovering the Timescales of Spin Reorientation in TbMn6Sn6, (potentially a different journal, still TBD) (Accessed October 11, 2025)