Title :
Observation of incoherent picosecond magnetisation dynamics in micron sized Ni81Fe19 elements by time resolved scanning Kerr effect microscopy
Author :
Barman, A. ; Kruglyak, V.V. ; Hicken, R.J. ; Kundrotaite, A. ; Rahman, M.
Author_Institution :
Sch. of Phys., Univ. of Exeter, UK
Abstract :
We have studied small amplitude magnetisation precession in a square Ni81Fe19 element by time resolved scanning Kerr effect microscopy. A single precessional mode was observed with a 1 μm diameter probe spot placed at the centre of the element. Using a coherent rotation model, the presence of a four-fold anisotropy of about 30 Oe was deduced. Time resolved images show that the dynamic magnetisation is initially nonuniform at the edges of the element, with the nonuniformity then extending towards the centre. The dynamic magnetisation is uniform at the centre of the element over the measurement time, justifying the use of the coherent rotation model in the analysis of the precession frequency.
Keywords :
Kerr magneto-optical effect; ferromagnetic materials; iron alloys; magnetisation; nickel alloys; optical microscopy; 0.5 micron; Ni-Fe; Ni81Fe19 elements; coherent rotation model; incoherent picosecond magnetisation dynamics; magnetic anisotropy; nonuniform dynamic magnetisation; optical pump-probe technique; precession frequency; precessional mode; probe spot diameter; scanning laser microscopy; small amplitude magnetisation precession; time resolved images; time resolved scanning Kerr effect microscopy;
Journal_Title :
Science, Measurement and Technology, IEE Proceedings -
DOI :
10.1049/ip-smt:20030868