Conditions for thermally induced all-optical switching in ferrimagnetic alloys: Modeling of TbCo

Moreno, R.; Ostler, Thomas; Chantrell, R.W.; Chubykalo‐Fesenko, O.

doi:10.1103/physrevb.96.014409

Cited by 49 publications

(46 citation statements)

References 47 publications

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“…In the past decade the spin dynamics of rare-earth transition-metal alloys has attracted intense research interest due to the unique capability of these materials to reverse their magnetization at record-breaking speed under the action of subpicosecond laser pulses [8]. In the research aiming to understand the mechanisms of the ultrafast laser-induced magnetization reversal computational methods have been playing a decisive role [9,11,13,[32][33][34]. It is clear that the value of the magnetic anisotropy of the rare-earth sublattice in ferrimagnets is an important input parameter which may greatly influence the outcome of such simulations.…”

Section: Resultsmentioning

confidence: 99%

“…Moreover, it is expected that in compounds with rare-earth ions with nonzero orbital momentum in the ground state (Tb, Dy, Sm), the effect of the rare-earth magnetic anisotropy will be even more pronounced than in the case of Gd. For instance, in the simulations of TbCo [33] in order to mimic the experimentally observed dependence of magnetic anisotropy on the concentration of Tb, it was necessary to set a 10 times larger anisotropy for the Tb sublattice compared to the one of Co. Our work provides an approach for experimental verification of element-specific magnetic anisotropies in rareearth transition-metal ferrimagnets.…”

Section: Resultsmentioning

confidence: 99%

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H−T phase diagram of rare-earth–transition-metal alloys in the vicinity of the compensation point

et al. 2019

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Anomalous hysteresis loops of ferrimagnetic amorphous alloys in high magnetic field in the vicinity of the compensation temperature have so far been explained by sample inhomogeneities. We obtain the H-T magnetic phase diagram for the ferrimagnetic GdFeCo alloy using a two-sublattice model in the paramagnetic rare-earth ion approximation and taking into account rare-earth (Gd) magnetic anisotropy. It is shown that if the magnetic anisotropy of the f sublattice is larger than that of the d sublattice, the tricritical point can be at higher temperature than the compensation point. The obtained phase diagram explains the observed anomalous hysteresis loops as a result of high-field magnetic phase transition, the order of which changes with temperature. It also implies that in the vicinity of the magnetic compensation point the shape of magnetic hysteresis loop strongly depends on temperature.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

H−T phase diagram of rare-earth–transition-metal alloys in the vicinity of the compensation point

et al. 2019

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“…Both sublattices have the same Curie temperature but their magnetizations have different temperature dependencies. Therefore, by changing the concentrations of 4f and 3d elements in the compound the compensation temperature, at which the magnetizations of the sublattices are mutually equal, and the net magnetization is zero, can be tuned in a wide range of temperatures, including room temperature 12 . At temperatures lower than the compensation temperature, the magnetization of the rare-earth (Tb) sublattice M f is larger than that of the transition metal (FeCo) M d , while for the temperatures above compensation point M f < M d .…”

Section: Introductionmentioning

confidence: 99%

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

et al. 2020

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Experimental studies of anomalous Hall effect are performed for thin filmed Ta/TbFeCo in a wide range of temperatures and magnetic fields up to 3 T. While far from the compensation temperature (T M =277 K) the field dependence has a conventional shape of a single hysteresis loop, just below the compensation point the dependence is anomalous having the shape of a triple hysteresis. To understand this behavior, we experimentally reveal the magnetic phase diagram and theoretically analyze it in terms of spinreorientation phase transitions. We show that one should expect anomalous hysteresis loops below the compensation point if in the vicinity of it the magnetic anisotropy is dominated by FeCo sublattice due to interaction with Ta. 19 , here the situation is inverted that the triple hysteresis is observed below T M . More particularly, using Hall bar structures of MgO/Ta/TbFeCo we measured field dependencies

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“…Unfortunately, Gd-based materials are inherently soft, making it difficult to downscale the size of Gd-based devices below the micrometer length-scales, whereas Tb is capable of supporting domains in continuous films of TbFeCo smaller than 50 nm 28 . Despite the fact that atomistic calculations predict 12 that single-shot HI-AOS can be achieved in amorphous TbFeCo alloys using femtosecond laser pulses, the practical capability of achieving this in any RE-TM system featuring Tb instead of Gd has, until now, remained undiscovered.…”

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confidence: 99%

Single-shot all-optical switching of magnetization in Tb/Co multilayer-based electrodes

Avilés-Félix

Olivier

Li³

et al. 2020

Sci Rep

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Ever since the first observation of all-optical switching of magnetization in the ferrimagnetic alloy GdFeCo using femtosecond laser pulses, there has been significant interest in exploiting this process for data-recording applications. in particular, the ultrafast speed of the magnetic reversal can enable the writing speeds associated with magnetic memory devices to be potentially pushed towards tHz frequencies. this work reports the development of perpendicular magnetic tunnel junctions incorporating a stack of tb/co nanolayers whose magnetization can be all-optically controlled via helicity-independent single-shot switching. toggling of the magnetization of the tb/co electrode was achieved using either 60 femtosecond-long or 5 picosecond-long laser pulses, with incident fluences down to 3.5 mJ/cm 2 , for co-rich compositions of the stack either in isolation or coupled to a cofeBelectrode/Mgo-barrier tunnel-junction stack. Successful switching of the cofeB-[tb/co] electrodes was obtained even after annealing at 250 °c. After integration of the [tb/co]-based electrodes within perpendicular magnetic tunnel junctions yielded a maximum tunneling magnetoresistance signal of 41% and RxA value of 150 Ωμm 2 with current-in-plane measurements and ratios between 28% and 38% in nanopatterned pillars. these results represent a breakthrough for the development of perpendicular magnetic tunnel junctions controllable using single laser pulses, and offer a technologically-viable path towards the realization of hybrid spintronic-photonic systems featuring tHz switching speeds. Ferrimagnetic systems based on rare earth (RE)-transition metal (TM) alloys and multilayers have been extensively studied in recent decades, largely due to their potential application in the field of magneto-optical recording 1. The strong perpendicular magnetocrystalline anisotropy inherent to amorphous RE-TM systems have allowed these alloys to play a key role in the historical transition from longitudinal to perpendicular magnetic recording structures 2 , and made them ideal for handling magnetic bit instabilities arising from superparamagnetic effects 3. Binary and ternary RE-TM systems such as GdFeCo, GdCo, TbCo or GdFe are still driving forward new developments pertaining to spintronic devices, including spin valves for magnetic read heads 4 , perpendicular magnetic tunnel junctions (p-MTJs) 5,6 or spin-orbit-torque phenomena 7. Recent works in this field have also revealed that RE-TM-based films (amorphous or multilayered) represent ideal materials for the observation and study of the phenomena of all-optical switching (AOS) 8-10. In these systems, it is possible to switch the magnetization using suitable laser pulses without the application of any external magnetic field. Depending on whether the laser-pulses need to be circularly-polarized, AOS of magnetization can be classed as either helicity-dependent (HD-AOS) or helicity-independent (HI-AOS). Furthermore, subject to the material in question, the switching process can be achieved with either a...

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Conditions for thermally induced all-optical switching in ferrimagnetic alloys: Modeling of TbCo

Cited by 49 publications

References 47 publications

H−T phase diagram of rare-earth–transition-metal alloys in the vicinity of the compensation point

H−T phase diagram of rare-earth–transition-metal alloys in the vicinity of the compensation point

Unusual Field Dependence of the Anomalous Hall Effect in Ta/Tb−Fe−Co

Single-shot all-optical switching of magnetization in Tb/Co multilayer-based electrodes

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