Universal Pinning Energy Barrier for Driven Domain Walls in Thin Ferromagnetic Films

Abstract

We report a comparative study of magnetic field driven domain wall motion in thin films made of different magnetic materials for a wide range of field and temperature. The full thermally activated creep motion, observed below the depinning threshold, is shown to be described by a unique universal energy barrier function. Our findings should be relevant for other systems whose dynamics can be modeled by elastic interfaces moving on disordered energy landscapes.

Universal domain wall dynamics under electric field in Ta/CoFeB/MgO devices with perpendicular anisotropy

“…Three DW dynamical regimes are observed, including the creep, intermediate depinning and depinning regimes1117192022. In all regimes the DW velocity increases (decreases) under positive (negative) voltage.…”

“…Although a dependence of U C on anisotropy is expected in the creep theory1011, this feature is consistent with recent results of modulation of anisotropy in Pt/Co/Pt32 and Ta/CoFeB/MgO33 films. Between these two regimes for 8 mT< μ 0 H <12 mT, an intermediate depinning regime occurs, which corresponds to the tails of the creep regime20 where the energy barriers vanish linearly as Δ E ∼( H / H dep −1) approaching H dep .…”

“…With increasing DW velocity in the creep regime, the electric field effect was found to be strongly reduced due to the decrease of the activation energies with applied magnetic fields5. So far, there has been no reports on the experimental observation of electric field effects beyond the creep regime, particularly in the depinning and flow regimes17181920.…”

Magnetic properties, domain-wall creep motion, and the Dzyaloshinskii-Moriya interaction in Pt/Co/Ir thin films

“…We show that the velocity scaling parameter, in addition to the energy barrier scaling parameter, changes as a function of applied in-plane bias field. We build on recent work on the creep motion of domain walls [19] to analyze the changes to the creep parameters. We describe how domain-wall roughness has an effect on how well the modified creep equation [7] models the domain-wall velocity when high in-plane bias fields are applied.…”

Spatiotemporal Patterns in Ultraslow Domain Wall Creep Dynamics

“…We foresee these correlated dynamics being experimentally accessible by magnetooptical imaging of ferromagnetic films. The physics of disordered elastic systems is relevant for many areas of physics such as magnetic [1][2][3][4][5] and ferroelectric [6,7] domain wall, contact lines in wetting [8], crack propagation [9,10], and vortex lines in type-II superconductors [11]. It involves the driven motion of an elastic object, such as a manifold or a periodic structure, in a weakly disordered medium.…”