Current-Induced Magnetization Switching with a Spin-Polarized Scanning Tunneling Microscope

Abstract

Switching the magnetization of a magnetic bit by injection of a spin-polarized current offers the possibility for the development of innovative high-density data storage technologies. We show how individual superparamagnetic iron nanoislands with typical sizes of 100 atoms can be addressed and locally switched using a magnetic scanning probe tip, thus demonstrating current-induced magnetization reversal across a vacuum barrier combined with the ultimate resolution of spin-polarized scanning tunneling microscopy. Our technique allows us to separate and quantify three fundamental contributions involved in magnetization switching (i.e., current-induced spin torque, heating the island by the tunneling current, and Oersted field effects), thereby providing an improved understanding of the switching mechanism.

Spin torque dynamics with noise in magnetic nanosystems

“…A number of experiments on current induced switching have been carried out previously [23][24][25][26][27] . From them it was found that the noise reduces the typical switching time, as one might expect.…”

Quantitative mapping of fast voltage pulses in tunnel junctions by plasmonic luminescence

“…Knowledge of the pulse profile reaching the tunnel junction is applied to optimize the experiment's time response by actively shaping the incident pulses. Scanning probe microscope studies focus increasingly on measuring fast time-dependent processes at atomic dimensions, such as spin [1][2][3][4] and charge 5,6 dynamics or molecular motion. [7][8][9][10] Heterodyne frequency mixing 11 and pump-probe excitation schemes 2,[12][13][14][15] have been put forward as techniques to measure repetitive variations of the tunnel current in a scanning tunneling microscope (STM).…”

On the superparamagnetic size limit of nanoparticles on a ferroelectric substrate

“…The general theory was applied by Néel [2] and subsequently by Brown [21] to small ferromagnetic single-domain grains/nanoparticles. During the last decades these theoretical findings were endorsed by experiments performed at low temperatures in the presence of static magnetic fields [17], ac-magnetic fields [22,23] or spin-polarized currents [24,25]. In the present study we focus on the composite multiferroic structure, depicted in Fig.…”