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Proceedings Paper

Current-induced switching and domain wall motion in magnetic insulators with perpendicular anisotropy (Conference Presentation)
Author(s): Can Onur Avci; Ethan Rosenberg; Andy Quindeau; Lucas Caretta; Maxwell Mann; Chi-Feng Pai; Lukas Beran; Manuel Baumgartner; Pietro Gambardella; Caroline A. Ross; Geoffrey S. D. Beach
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Paper Abstract

Magnetic insulators (MIs), especially iron-based garnets, possess remarkable properties such as ultralow damping and long magnon decay lengths, which can provide significant advantages for practical applications with respect to their metallic magnetic counterparts. Recently, robust perpendicular magnetic anisotropy (PMA) is obtained in ferrimagnetic films of thulium, europium, and terbium iron garnet (TmIG, EuIG, and TbIG) with high structural quality down to a thickness of 5.6 nm with saturation magnetization close to bulk [1,2]. By using the spin Hall effect in platinum we have demonstrated efficient spin current injection through the TmIG/Pt interface, which we quantified by the spin Hall magnetoresistance and harmonic Hall effect measurements [1-3]. We then achieved deterministic spin-orbit torque-driven magnetization switching of TmIG(~10 nm)/Pt bilayer both with quasi-dc (5 ms) as well as pulsed currents down to 2 ns width[1,4]. The switching current density is found to be of the order of ~10^7 (~10^8) A/cm2 using dc (pulsed) current, comparable to reported values for Pt/Co[5]. We reveal that the threshold switching current strongly depends on the absence or presence of an initially reversed domain in the structure implying a reversal mediated by efficient current-driven domain wall motion. Ultimately, we investigated the current-driven dynamics of domain walls in TmIG. We found that by solely using electrical currents, domain walls can be efficiently moved with very high mobility. Moreover, the flow regime threshold is found to be an order of magnitude lower with respect to conventional ferromagnets with interfacial PMA, owing to structural quality and bulk-like behavior of 7-nm-thick TmIG. These results suggest the utility of PMA rare earth garnets and pave the road towards ultralow dissipation spintronic devices based on MIs. [1] Avci et al., Nat. Mater. 16, 309 (2017); [2]Quindeau et al., Adv. Elec. Mater. 3, 1600376 (2017); [3]Avci et al., PRB 95, 115428 (2017); [4]Avci et al., APL 111, 072406 (2017); [5]Miron et al., Nature 476, 189 (2011).

Paper Details

Date Published: 18 September 2018
Proc. SPIE 10732, Spintronics XI, 107322B (18 September 2018); doi: 10.1117/12.2320915
Show Author Affiliations
Can Onur Avci, Massachusetts Institute of Technology (United States)
Ethan Rosenberg, Massachusetts Institute of Technology (United States)
Andy Quindeau, Massachusetts Institute of Technology (United States)
Lucas Caretta, Massachusetts Institute of Technology (United States)
Maxwell Mann, Massachusetts Institute of Technology (United States)
Chi-Feng Pai, Massachusetts Institute of Technology (United States)
Lukas Beran, Massachusetts Institute of Technology (United States)
Manuel Baumgartner, ETH Zurich (Switzerland)
Pietro Gambardella, ETH Zurich (Switzerland)
Caroline A. Ross, Massachusetts Institute of Technology (United States)
Geoffrey S. D. Beach, Massachusetts Institute of Technology (United States)

Published in SPIE Proceedings Vol. 10732:
Spintronics XI
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi; Henri Jaffrès, Editor(s)

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