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|Title:||ALS-CXRO Seminar Series: Mi-Young Im|
|When:||09/12/2013 1:00 PM - 2:00 PM|
|Description:||ALS Special Seminar|
Thursday, September 12, 2013
2-400F Conference Room
Mi-Young Im (LBNL)
"X-ray Microscopy Studies of Asymmetric and Stochastic Behaviors in Spin Structures"
Asymmetry and stochasticity in nanomaterials are not only long-standing fundamental issues but also highly relevant to technological applications of nanostructures. Those nontrivial phenomena have been studied by direct imaging of spin structures in magnetic vortex systems utilizing transmission soft x-ray microscopy (BL6.1.2 at ALS). We observed a symmetry breaking and a stochastic behavior in the formation process of vortex structures in circular and asymmetric shaped permalloy (Ni80Fe20) disks, respectively. It is interpreted that the symmetry breaking in circular disks is triggered by “intrinsic” Dzyaloshinskii-Moriya interaction (DMI) arising from the spin-orbit coupling due to the lack of inversion symmetry near the disk surface and “extrinsic” factors such as roughness and defects. The chaotic dynamic process is deeply involved in the stochastic behavior observed in asymmetric disks. In addition to the asymmetry and stochasticity, I will discuss the possibility to control spin behavior and its intrinsic nature which is a critical matter for application of spin systems to data storage technologies.
|Location:||2-400F Conf Room|