Interface enhanced precessional damping in spintronic multilayers: A perspective

In the past two decades, there have been huge developments in the understanding of damping in multilayered thin films and, more generally, in spin-transport in spintronic systems. In multilayered ferromagnetic (FM)/non-magnetic (NM) thin-film systems, observations of ferromagnetic resonant precession show a strong increase in the fundamental damping when the FM thin films are layered with heavy metals, such as Pt. These observations led to significant theoretical developments, dominated by the “spin-pumping” formalism, which describes the enhancement of damping in terms of the propagation or “pumping” of spin-current across the interface from the precessing magnetization into the heavy metal. This paper presents a perspective that introduces the key early experimental damping results in FM/NM systems and outlines the theoretical models developed to explain the enhanced damping observed in these systems. This is followed by a wider discussion of a range of experimental results in the context of the theoretical models, highlighting agreement between the theory and experiment, and more recent observations that have required further theoretical consideration, in particular, with respect to the role of the interfaces and proximity-induced magnetism in the heavy metal layer. The Perspective concludes with an outline discussion of spin-pumping in the broader context of spin-transport.

[1]  P. Kuświk,et al.  Proximity-induced magnetism and the enhancement of damping in ferromagnetic/heavy metal systems , 2021, Applied Physics Letters.

[2]  P. Muduli,et al.  Proximity effect induced enhanced spin pumping in Py/Gd at room temperature , 2018, Applied Physics Letters.

[3]  Di Wu,et al.  Self-consistent determination of spin Hall angle and spin diffusion length in Pt and Pd: The role of the interface spin loss , 2018, Science Advances.

[4]  M. Belmeguenai,et al.  Ferromagnetic-resonance-induced spin pumping in Co20Fe60B20/Pt systems: damping investigation , 2018 .

[5]  K. Ollefs,et al.  Investigating magnetic proximity effects at ferrite/Pt interfaces , 2017 .

[6]  D. Atkinson,et al.  Magnetic damping phenomena in ferromagnetic thin-films and multilayers , 2017 .

[7]  T. Hase,et al.  The interfacial nature of proximity-induced magnetism and the Dzyaloshinskii-Moriya interaction at the Pt/Co interface , 2017, Scientific Reports.

[8]  Michael L. Schneider,et al.  Ultra-low magnetic damping of a metallic ferromagnet , 2015, Nature Physics.

[9]  J. King,et al.  Tunable Magnetization Dynamics in Interfacially Modified Ni81Fe19/Pt Bilayer Thin Film Microstructures , 2015, Scientific Reports.

[10]  Yajun Wei,et al.  On the frequency and field linewidth conversion of ferromagnetic resonance spectra , 2015 .

[11]  Xin Jiang,et al.  Role of transparency of platinum–ferromagnet interfaces in determining the intrinsic magnitude of the spin Hall effect , 2015, Nature Physics.

[12]  Del Atkinson,et al.  Local control of magnetic damping in ferromagnetic/non-magnetic bilayers by interfacial intermixing induced by focused ion-beam irradiation. , 2014 .

[13]  Kazuya Ando,et al.  Dynamical generation of spin currents , 2014 .

[14]  W. Pratt,et al.  Spin-Flipping in Pt and at Co/Pt Interfaces , 2013, 1310.4364.

[15]  D. Atkinson,et al.  Suppression of Walker breakdown in magnetic domain wall propagation through structural control of spin wave emission , 2013 .

[16]  K. Baberschke Ferromagnetic resonance in nanostructures, rediscovering its roots in paramagnetic resonance , 2011 .

[17]  Y. Otani,et al.  Manipulation of spin currents in metallic systems , 2011, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[18]  S. Bandiera,et al.  Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection , 2011, Nature.

[19]  Gerrit E. W. Bauer,et al.  Spin transfer torque on magnetic insulators , 2011, 1103.3764.

[20]  E. R. Lewis,et al.  Fast domain wall motion in magnetic comb structures. , 2010, Nature materials.

[21]  M. Stiles,et al.  Spin-orbit precession damping in transition metal ferromagnets (invited) , 2008, 0801.0549.

[22]  J. Ferré,et al.  Domain wall mobility, stability and Walker breakdown in magnetic nanowires , 2007, cond-mat/0702492.

[23]  W. Pratt,et al.  Spin-diffusion lengths in metals and alloys, and spin-flipping at metal/metal interfaces: an experimentalist’s critical review , 2006, cond-mat/0610085.

[24]  Eiji Saitoh,et al.  Conversion of spin current into charge current at room temperature: Inverse spin-Hall effect , 2006 .

[25]  A. Brataas,et al.  Scattering of spin current injected in Pd(001) , 2005 .

[26]  R. Loloee,et al.  Spin-memory loss at 4.2 K in sputtered Pd and Pt and at Pd/Cu and Pt/Cu interfaces , 2002 .

[27]  L. Berger Effect of interfaces on Gilbert damping and ferromagnetic resonance linewidth in magnetic multilayers , 2001 .

[28]  L. Berger Precession of conduction-electron spins near an interface between normal and magnetic metals , 1995 .

[29]  Roy W. Chantrell,et al.  A method for the numerical simulation of the thermal magnetization fluctuations in micromagnetics , 1993 .

[30]  B. Heinrich,et al.  FMR linebroadening in metals due to two‐magnon scattering , 1985 .

[31]  N. L. Schryer,et al.  The motion of 180° domain walls in uniform dc magnetic fields , 1974 .

[32]  V. Kamberský On the Landau-Lifshitz relaxation in ferromagnetic metals , 1970 .