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Gang Xiao

Publications and source records attributed to Gang Xiao.

22 records · Page 2Linked to original sources
arXiv2015

Scanning Kerr microscopy of current induced switching in Ta/CoFeB/MgO films with perpendicular magnetic anisotropy

Ta/CoFeB/MgO trilayers with perpendicular magnetic anisotropy are expected to play a key role in the next generation of current and electric field switched memory and logic devices. In this study we use Kerr microscopy alongside electrical transport measurement to gain insight into the underlying switching mechanisms of such devices. We find switching to be a stochastic, domain wall driven process, the speed of which is strongly dependent on the switching current. Kerr imaging shows domain nucleation at the edge of the device which modelling reveals is likely assisted by the perpendicular component of the Oersted field. Further domain growth, leading to magnetisation reversal may be assisted by spin torques.

cond-mat.mtrl-sci↗
arXiv2004

Tunable magnetization damping in transition metal ternary alloys

We show that magnetization damping in Permalloy, Ni80Fe20 (``Py''), can be enhanced sufficiently to reduce post-switching magnetization precession to an acceptable level by alloying with the transition metal osmium (Os). The damping increases monotonically upon raising the Os-concentration in Py, at least up to 9% of Os. Other effects of alloying with Os are suppression of magnetization and enhancement of in-plane anisotropy. Magnetization damping also increases significantly upon alloying with the five other transition metals included in this study (4d-elements: Nb, Ru, Rh; 5d-elements: Ta, Pt) but never as strongly as with Os.

cond-mat.mtrl-sci↗
arXiv2002

The role of electron scattering in magnetization relaxation in thin Ni$_{81}$Fe$_{19}$ films

We observe a strong correlation between magnetization relaxation and electrical resistivity in thin Permalloy (Ni$_{81}$Fe$_{19}$, ``Py'') films. Electron scattering rates in the films were affected by varying film thickness and deposition conditions. This shows that the magnetization relaxation mechanism is analogous to ``bulk'' relaxation, where phonon scattering in bulk is replaced by surface and defect scattering in thin films. Another interesting finding is the increased magnetization damping with Pt layers adjacent to the Py films. This is attributed to the strong spin-orbit coupling in Pt, resulting in spin-flip scattering of electrons that enter from the Py.

cond-mat.mtrl-sci↗