Nanosecond pulsed field magnetization reversal in thin-film NiFe studied by Kerr effect magnetometry

Atkinson, D.; Allwood, D. A.; Cooke, Mary; Cowburn, R. P.

doi:10.1088/0022-3727/34/20/303

Cited by 8 publications

(2 citation statements)

References 16 publications

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“…The measurements were made using either a pulsed field or a swept field to precipitate the magnetization reversal. Squares: swept field, NiFe, [20]; circles: pulsed field, NiFe, [21][22][23][24]; upright triangles: swept field, Fe, [25]; inverted triangles: swept field, Co, [17]. The solid curve corresponds to the field H prec necessary to switch a magnetic moment by precession on the timescale of t exp .…”

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confidence: 99%

Mesofrequency dynamic hysteresis in thin ferromagnetic films

Moore¹,

Bland

2004

J. Phys.: Condens. Matter

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The spectrum of timescales for thin film magnetization reversal processes from 10 3 to 10 −15 s is reviewed as well as appropriate experimental techniques for their investigation. The present review is motivated by the fact that most studies of magnetization dynamics have used polycrystalline NiFe thin films, whilst the magnetization dynamics of epitaxial Fe thin films, in contrast, have been little investigated, especially in the mesofrequency range (10 −1 -10 −6 s). Here, the competition between domain nucleation and domain wall propagation reversal processes results in a rich variety in the dynamical behaviour. We review the results of our time-resolved magneto-optic Kerr effect measurement of the dynamic hysteresis loop in epitaxial Fe thin films. Coercivity as a function of applied field frequency H c ( f ) is measured from the dynamic hysteresis loop in the frequency range ∼0.03-3000 Hz, corresponding to experimental timescales t exp ≈ H c / Ḣ in the range ∼10 −1 -10 −6 s, where Ḣ is the applied field sweep rate at the static coercive field H c . Not only are two distinct dynamic regimes for H c ( f ) found to arise in the experimental timescale range 10 −1 -10 −6 s, but also the reversal processes of domain nucleation and wall propagation are seen to compete at the crossover between the two dynamic regimes, so determining the behaviour of H c ( f ). This review gives a historical overview of dynamic hysteresis in the mesofrequency range, and surveys recent theoretical descriptions and experiments. It is demonstrated that dynamic hysteresis experiments on thin ferromagnetic films are richly informative of the magnetization dynamics in the mesofrequency range. Methods for the interpretation of dynamic coercive field measurements H c ( f ) are highlighted, including an adaptation of an existing model of magnetization reversal dynamics in ultrathin magnetic layers.

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Section: Figurementioning

confidence: 99%

Mesofrequency dynamic hysteresis in thin ferromagnetic films

Moore¹,

Bland

2004

J. Phys.: Condens. Matter

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“…Wire widths ranged from 800 nm down to 200 nm and the wire length was 50 mm. A further level of fabrication produced 30 mm wide microstrip line conductors of 30 nm thick aluminium overlapping one end of each wire (a copper ground plane was added to the base of the substrate to complete the transmission line [4]). …”

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