Magnetization Reversal in Ultrashort Magnetic Field Pulses

Back, Christian; Weller, D.; Heidmann, J.; Mauri, D.; Guarisco, D.; Garwin, E. L.; Siegmann, H. C.

doi:10.1103/physrevlett.81.3251

Cited by 192 publications

(152 citation statements)

References 17 publications

Supporting

Mentioning

146

Contrasting

Order By: Relevance

“…The present strategy should be compared with those of the SW and the precessional pico-second magnetization reversal. 11,12 As illustrated in Figs. 2͑b͒ and 2͑c͒, the SW strategy is to apply a large enough field to destroy the minimum initial state so that the particle can end up in the target state ͓Fig.…”

Section: Strategymentioning

confidence: 97%

“…10 is not the optimum. In fact, a circularly polarizedlike microwave ͑around 100 GHz for a Co film 11 ͒ is enough to switch a magnetization. The present strategy should be compared with those of the SW and the precessional pico-second magnetization reversal.…”

Section: Strategymentioning

confidence: 99%

“…This problem was first studied by Stoner and Wohlfarth 4 ͑SW͒ who showed that a field h larger than the SW-limit h SW can switch the magnetization from its initial state to the target value through a ringing effect. [5][6][7][8][9] However, recent theoretical and experimental studies [8][9][10][11][12] have shown that the minimal switching field can be smaller than the SW limit. Most studies have assumed the magnetic field to be time independent.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Strategy to reduce minimal magnetization switching field for Stoner particles

Zhen

Wang

2006

Phys. Rev. B

View full text Add to dashboard Cite

A strategy is proposed aimed at substantially reducing the minimal magnetization switching field for a Stoner particle. Unlike the normal method of applying a static magnetic field which must be larger than the magnetic anisotropy, a much weaker field, proportional to the damping constant in the weak damping regime, can be used to switch the magnetization from one state to another if the field is along the motion of the magnetization. The concept is to constantly supply energy to the particle from the time-dependent magnetic field to allow the particle to climb over the potential barrier between the initial and the target states.

show abstract

Section: Strategymentioning

confidence: 97%

Section: Strategymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Strategy to reduce minimal magnetization switching field for Stoner particles

Zhen

Wang

2006

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…In the dissipationless case, the maximal sweep speed is given by Eq. (12). For that speed one obtains the minimal reversal time…”

Section: B Optimal Frequency Sweepmentioning

confidence: 99%

Reversal of magnetization of a single-domain magnetic particle by the ac field of time-dependent frequency

2013

View full text Add to dashboard Cite

We report numerical and analytical studies of the reversal of the magnetic moment of a singledomain magnetic particle by a circularly polarized ac field of time-dependent frequency. For the time-linear frequency sweep, the phase diagrams are computed that illustrate the dependence of the reversal on the frequency sweep rate v, the amplitude of the ac field h, the magnetic anisotropy field d, and the damping parameter α. It is shown that the most efficient magnetization reversal requires a non-linear time dependence of the frequency, ω(t), for which an exact analytical formula is derived with account of damping. The necessary condition of the reversal is h > αd. Implementation of a small-scale magnetization reversal is proposed in which a nanomagnet is electromagnetically coupled to two weak superconducting links controlled by the voltage. Dynamics of such a system is analyzed with account of the back effect of the magnet on the superconducting links.

show abstract

“…Magnetization reversal using the ultrafast IFE is therefore similar to precessional switching in an applied magnetic field, [24][25][26] although the IFE has the advantage that optical pulses can be made much shorter than magnetic pulses. For short pulses, dissipation is known to be of minor importance 26 and is neglected here.…”

mentioning

confidence: 99%

Conservation of angular momentum and the inverse Faraday effect

Woodford

2009

Phys. Rev. B

View full text Add to dashboard Cite

Precession of magnetization via the inverse Faraday effect is investigated with a view of determining the fundamental limit on the precession speed. Such a limit could have important consequences for ultrafast magnetic switching. The angular momentum required for precession is shown to be supplied by the light. This indicates that there is no fundamental obstruction to magnetization reversal on the time scale of a laser pulse provided that a material with a sufficiently strong magneto-optical response can be found. DOI: 10.1103/PhysRevB.79.212412 PACS number͑s͒: 75.60.Jk, 75.40.Gb, 78.20.Ls, 85.70.Li The ability to control magnetization on a subpicosecond time scale is growing in importance as the speed of electronic devices increases. The current generation of technology employs magnetic fields to induce magnetization dynamics. However, due to the difficulty of creating ultrashort magnetic pulses and the recent discovery that magnetic switching by strong magnetic fields can be unpredictable, 1 alternative techniques of controlling magnetization are under intense investigation. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Optical methods 2-13 are particularly promising due to the availability of ultrashort laser pulses. However, the fundamental mechanisms of optically induced demagnetization and magnetic switching are not fully understood. In particular, the question of which reservoir supplies the angular momentum needed for demagnetization remains controversial. This reservoir plays a decisive role in determining the maximum demagnetization speed so resolving this issue is important for technological applications.Most experiments on optical demagnetization and magneto-optical switching employ thermal methods. An optical pulse is absorbed, the electrons are driven far from equilibrium, and the sample is almost completely demagnetized within a few hundred femtoseconds. [3][4][5][6][7][8][9][10] If this is performed in the presence of a magnetic field, the magnetization can be reversed. [2][3][4][5] Some estimates show that thermal demagnetization occurs too rapidly for phonon processes to be relevant and it has been suggested that angular momentum is transferred between the spin and orbital components of the electrons. 9 On the other hand, it is possible that the nonequilibrium electrons experience a spin-phonon interaction that is much stronger than usual. In this case, the phonons could provide the angular momentum. 8,10 Transfer of angular momentum by the absorption of photons has also been considered. 9,13,18 Theoretical arguments based on the number of photons absorbed 9 and experiments using circularly polarized light with nickel 18 indicate that the photon angular momentum is irrelevant, although experiments with GdFeCo yielded the opposite conclusion. 13 Thermomagnetic switching is associated with an increase in temperature, so devices employing these methods will suffer a significant cooling time before new information can be written to them. The inverse Faraday effect ͑IFE͒ offers the p...

show abstract

Magnetization Reversal in Ultrashort Magnetic Field Pulses

Cited by 192 publications

References 17 publications

Strategy to reduce minimal magnetization switching field for Stoner particles

Strategy to reduce minimal magnetization switching field for Stoner particles

Reversal of magnetization of a single-domain magnetic particle by the ac field of time-dependent frequency

Conservation of angular momentum and the inverse Faraday effect

Contact Info

Product

Resources

About