Take a sneak peek at the new NIST.gov and let us know what you think!
(Please note: some content may not be complete on the beta site.).
NIST Authors in Bold
|Author(s):||N D. Rizzo; Thomas J. Silva; Anthony B. Kos;|
|Title:||Nanosecond Magnetization Reversal in High Coercivity Thin Films|
|Published:||January 01, 2000|
|Abstract:||We used a wide-field Kerr microscope to measure magnetization reversal in high coercivity thin film media that were subjected to nanosecond field pulses. Coplanar waveguides were used as a field source. Two different samples of CoCr10Ta4 were measured. Sample A had a coercivity of 83 kA/m and sample B had a coercivity of 167 kA/m. For sample A, we find that after a step change in H. the magnetization initially relaxes exponentiallywith a time constant of 5 ns, and then relaxes logarithmically. We interpret this result as indicating a transition from dynamic reversal to thermal relaxation. In higher fields, the exponential relaxation time decreases according to τ = Sw/(H - Ho). where Sw = 29.7 5s 7 A 7 m-1(373 ns 7 Oe). For sample B, only logarithmic relaxation is observed, implying that the dynamic magnetization response time is subnanosecond. We observe correlated regions of reversed magnetization in our Kerr images of sample A with a typical correlation length of 1 5m along the applied field direction. We propose a microscopic model of nucleation and growth of reversed regions by analogy to viscous domain wall motion.|
|Citation:||IEEE Transactions on Magnetics|
|Pages:||pp. 159 - 165|
|Keywords:||coplanar,high speed magnetization reversal,Kerr microscope,thinfilm media,waveguide|