CoFe stripes: Magnetization reversal study by polarized neutron scattering and magneto-optical Kerr effect

Abstract

We have studied the magnetization reversal of a laterally structured film with both, magneto-optical Kerr effect and with polarized neutron scattering in the off-specular regime. The lateral structure consists of 90-nm thick and 1.2-m wide Co 0.7 Fe 0.3 stripes with a grating period of 3 m. Magnetization reversals were measured for different orientations of the sample with respect to the field directions. In addition, Kerr microscopy was used for visualizing the domain state. Due to the high aspect ratio of the individual stripes, the remagnetization process of the stripe array is dominated by a single domain state over most of the field range. For the easy axis direction, a nucleation and domain wall movement is observed at the coercive field. However, for all other orientations of the stripe array the magnetization reversal is dominated by a coherent magnetization rotation up to the coercive field. For the hard axis orientation the coherent rotation is complete. For this particular stripe array, the agreement between results obtained from MOKE and PNS experiments is very good, mainly due to the specific sample design chosen.

Voltage-induced modification in magnetic coercivity of patterned Co50Fe50 thin film on piezoelectric substrate

“…In H ? case, reversal occurs much smoother indicating dominant coherent rotation of spins with partial domain nucleation at H c [18].…”

“…4, the elongate shape of stripes favors breaking of the in-plane isotropic distribution of anisotropy axis, that leads domain magnetization directions to reorient closer to the stripe length. However, a strong uniaxial anisotropy along stripe direction is still not established, as expected in narrower Co 50 Fe 50 stripes [18], since a typical hard axis hysteresis loop is not observed when H ? .…”

The influence of finite size and shape anisotropy on exchange bias: A study of patterned Co/CoO nanostructures

“…For these experiments, the attention was focussed on the off-specular reflectivity, which shows intense satellite peaks due to the in-plane periodicity of the dot array. It was previously demonstrated that off-specular PNR can reveal in-plane structures and that the spin-analyzed intensity of a satellite peak as function of the applied field allows to monitor the magnetization reversal process [17][18][19][20]. The specular reflectivity is largely dominated by the nonmagnetic Si substrate, and, therefore, does not contribute any information about the magnetic state of the bars.…”

Magnetization reversal of periodic arrays of magnetic elements

“…This method has provided invaluable information on exchange coupling [4,5], on exchange bias [6][7][8][9][10][11][12], and on the complex magnetism of ultrathin films [13][14][15]. Most recently, it has been demonstrated that neutron scattering can also be used for studying the re-magnetization process of patterned magnetic structures [16][17][18][19][20]. From polarized neutron scattering, information from the specular as well as from Bragg reflections of a periodic pattern can be obtained at small angles.…”