Deterministic character of all-optical magnetization switching in GdFe-based ferrimagnetic alloys

Abstract

Using photoemission electron microscopy with x-ray magnetic circular dichroism as a contrast mechanism, new insights into the all-optical magnetization switching (AOS) phenomenon in GdFe-based rare-earth transitionmetal ferrimagnetic alloys are provided. From a sequence of static images taken after single linearly polarized laser pulse excitation, the repeatability of AOS can be quantified with a correlation coefficient. It is found that low coercivity enables thermally activated domain-wall motion, limiting in turn the repeatability of the switching. Time-resolved measurements of the magnetization dynamics reveal that while AOS occurs below and above the magnetization compensation temperature T M , it is not observed in GdFe samples where T M is absent. Finally, AOS is experimentally demonstrated against an applied magnetic field of up to 180 mT.

Steering of magnetic domain walls by single ultrashort laser pulses

“…The simulations show that the film transiently demagnetizes in a certain area around the center of the laser spot, where the lattice temperature exceeds the Curie temperature of Fe 75 Gd 25 of about 600 K [10]. This demagnetization probably provides the thermal depinning of the domain wall discussed before.…”

“…Besides domain-wall motion by magnetic fields and electric currents, laser-induced manipulation of magnetization is considered particularly interesting with respect to speed and power consumption [4]. Deterministic switching of magnetization by circularly polarized laser light has been demonstrated in magnetic insulators [5], semiconductors [6], as well as in metallic ferrimagnetic alloys and multilayers [7][8][9][10]. This allows to use ultrashort laser pulses for writing or processing magnetic information.…”

Magnetization compensation and spin reorientation transition in ferrimagnetic DyCo5 : Multiscale modeling and element-specific measurements

“…For Tb, Dy, and Er, there exists a compensation temperature where the magnetizations of the Co and RE sublattices fully cancel each other [5][6][7]. Such a compensation point is seen as a prerequisite for thermally induced magnetization switching, where the magnetization is toggled by a fs-laser pulse on a sub-ps time scale [8][9][10][11], making these compounds promising research objects in the field of ultrafast magnetism. Additionally, there is a spin reorientation transition (SRT) in the RCo 5 compounds for Pr, Nd, Tb, Dy, and Ho, where the magnetization rotates from either an easy-basal plane (EBP) or easy cone (EC) to an easy c axis (EA) [12,13].…”

Spatially resolved investigation of all optical magnetization switching in TbFe alloys

“…Although heat dominated domain wall motion has been considered as a limitation for deterministic switching in GdFeCo films 26 , the switching mechanism for our measurements in TbFe films instead requires heat induced domain wall motion in order to form large switched domains. At room temperature, the stimulus by the laser is not enough to switch the magnetization.…”