Magnetization reversal of individual, isolated high-aspect-ratio Fe nanoparticles with diameters comparable to the magnetic exchange length is studied by high-sensitivity submicron Hall magnetometry. For a Fe nanoparticle with diameter of 5nm, the magnetization reversal is found to be an incoherent process with localized nucleation assisted by thermal activation, even though the particle has a single-domain static state. For a larger elongated Fe nanoparticle with a diameter greater than 10nm, the inhomogeneous magnetic structure of the particle plays important role in the reversal process.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2005 Jun 1|