Magneto-optical Kerr effect susceptometer for the analysis of magnetic domain wall dynamics

Abstract

Articles you may be interested inMagnetic susceptibility measurements of ultrathin films using the surface magneto-optic Kerr effect: Optimization of the signal-to-noise ratio Rev.

Direct imaging of nanoscale field-driven domain wall oscillations in Landau structures

“…Our observations indicate that even at f ac = 1 kHz the DW is still instantaneously following the excitation field. Studies performed by Kerr susceptometry on Co 2 MnGe 33 and Co 32 stripes report dependencies of the DW oscillation amplitude on both, excitation amplitude and frequency. For a fixed excitation amplitude, the DW oscillation amplitude varies with excitation frequency.…”

Domain wall dynamics of periodic magnetic domain patterns in Co2MnGe-Heusler microstripes

“…MOKE experiments were carried out at room temperature by varying the frequency in a range of 0.5 Hz<f< 100 Hz and the amplitude in a range of 0.4 mT<μ 0 H 0 < 8.8 mT. For sideways DW slide motion in a regular magnetic stripe pattern, Kataja and van Dijken in [15] derived analytical expressions (see equation (1)) to describe the normalized X n and Y n components as a function of the frequency f and field amplitude H 0 as:…”

“…In this regime, the net average wall velocity first decreases with increasing H, until, for H?H W the net motion results again in an asymptotically linear H-v DW function, but now with a mobility given by μ DW =γΔ/(α+α −1 ). Based on this formalism, Kataja and van Dijken [15] proposed a model considering an alternating (ac) driving field H=H 0 cosωt. Under ac-field excitation DW creep and slide modes can be activated in dependence on the amplitude and frequency of the field.…”

“…Under ac-field excitation DW creep and slide modes can be activated in dependence on the amplitude and frequency of the field. The model proposed in [15] describes the complex Kerr signal (V Kerr =X−iY) as a function of field amplitude (H 0 ) and driving frequency (f=ω/2π) to describe the DW slide regime of regular magnetic domain patterns. This model allows to obtain DW mobility and depinning fields.…”

Materials Degradation and Detection (MD2): Deep Dive Final Report

“…A similar experiment using a MOKE microscope known as a magneto-optical microscope magnetometer (MOMM) has been used to plot probabilities of Barkhausen jump sizes as a function of NiO thickness on Fe, showing that mechanisms of domain wall creep can be distinguished from domain wall pinning and depinning (Barkhausen) (Lee et al 2011). Finally, MOKE magnetometry has been used to study the effects of AC magnetic fields on domain walls, allowing the differentiation between domain boundary creep, slide, and switching as a function of AC field excitation frequency, and allowing the accurate measurement of depinning fields and domain wall mobility (Kataja and van Dijken 2011). In summary, magnetic imaging methods such as MFM and MOKE provide a critical experimental tool to obtain numerical parameters (such as depinning fields, domain wall mobilities, etc.)…”