Real time probing of magnetization switching in magnetic nanostructures

Abstract

Time-resolved anisotropic magnetoresistance ͑AMR͒ measurements of the irreversible switching of the magnetization were performed on isolated Ni nanowires. The magnetization reversal was triggered by injection of high current densities in a static magnetic field. The detection was achieved by means of a Wheatstone bridge with a 1 GHz bandwidth. Time-resolved switching was obtained in single shot measurements. Nanowires with diameter of about 100 nm that present a uniform rotation in the reversible regime detected in quasistatic AMR measurements are found to have switching in about 14 ns. This value can be accounted for in the framework of an uniform rotation model with value of the Gilbert damping coefficient of 0.005-0.01. Nanowires with larger diameters ͑typ. 200 nm͒ that manifest inhomogeneous magnetization in quasistatic AMR measurements have a switching time of about 37 ns.

Spin-dependent Peltier effect of perpendicular currents in multilayered nanowires

“…The temperature of the wires under currents of high density was monitored by resistance measurements. 13 The temperature rise is of no more than a few K for wires about 50 nm in diameter. 14 The magnetothermoelectrical power ͑MTEP͒ measurement shows the dependence on the magnetic field of the thermoelectric power, in other words, of the effective Seebeck coefficient of the multilayers.…”

Real time magnetisation reversal dynamics in epitaxial Fe/GaAs(001)

“…Magnetisation dynamics in thin metallic films is an increasingly popular field of study [1][2][3]. Research is driven both by fundamental interest in the nature of switching in magnetic structures and by a quest for fast, well-controlled magnetisation reversal that is required for devices.…”