arXiv subjects

K. Thiel

Publications and source records attributed to K. Thiel.

2 recordsLinked to original sources

arXiv2009

Electric breakdown in ultra-thin MgO tunnel barrier junctions for spin-transfer torque switching

Magnetic tunnel junctions for spin-transfer torque switching were prepared to investigate the dielectric breakdown. The breakdown occurs typically at voltages not much higher than the switching voltages, a bottleneck for the implementation of spin-transfer torque Magnetic Random Access Memory. Intact and broken tunnel junctions are characterized by transport measurements and then prepared for transmission electron microscopy and energy dispersive x-ray spectrometry by focussed ion beam. The comparison to our previous model of the electric breakdown for thicker MgO tunnel barriers reveals significant differences arising from the high current densities.

cond-mat.mtrl-sci↗

arXiv2008

Direct imaging of the structural change generated by dielectric breakdown in MgO based magnetic tunnel junctions

MgO based magnetic tunnel junctions are prepared to investigate the dielectric breakdown of the tunnel barrier. The breakdown is directly visualized by transmission electron microscopy measurements. The broken tunnel junctions are prepared for the microscopy measurements by focussed ion beam out of the junctions characterized by transport investigations. Consequently, a direct comparison of transport behavior and structure of the intact and broken junctions is obtained. Compared to earlier findings in Alumina based junctions, the MgO barrier shows much more microscopic pinholes after breakdown. This can be explained within a simple model assuming a relationship between the current density at the breakdown and the rate of pinhole formation.

cond-mat.mtrl-sci↗