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

Donges, Andreas; Khmelevskyi, Sergii; Deák, András; Abrudan, R.; Schmitz, D.; Radu, Ilie; Radu, F.; Szunyogh, L.; Nowak, Ulrich

doi:10.1103/physrevb.96.024412

Cited by 21 publications

(15 citation statements)

References 51 publications

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“…3(a) we plot the coercive field of the hysteresis loops and the shift of the side hysteresis loops as a function of temperature. The divergence of the coercive field, which occurs at the vanishing net magnetization of the film, reveals with good accuracy the absolute value of the intrinsic T comp which is about 154 K, in close agreement with previous experiments and simulation results [36,37]. Also, we plot the field of the center of the wing hysteresis loops as a function of temperature, denoted as exchange bias field H eb .…”

Section: Resultssupporting

confidence: 88%

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

Luo

Ryll

Back

et al. 2019

Sci Rep

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Ferrimagnetic alloys are extensively studied for their unique magnetic properties leading to possible applications in perpendicular magnetic recording, due to their deterministic ultrafast switching and heat assisted magnetic recording capabilities. On a prototype ferrimagnetic alloy we demonstrate fascinating properties that occur close to a critical temperature where the magnetization is vanishing, just as in an antiferromagnet. From the X-ray magnetic circular dichroism measurements, an anomalous ‘wing shape’ hysteresis loop is observed slightly above the compensation temperature. This bears the characteristics of an intrinsic exchange bias effect, referred to as atomic exchange bias. We further exploit the X-ray magnetic linear dichroism (XMLD) contrast for probing non-collinear states which allows us to discriminate between two main reversal mechanisms, namely perpendicular domain wall formation versus spin-flop transition. Ultimately, we analyze the elemental magnetic moments for the surface and the bulk parts, separately, which allows to identify in the phase diagram the temperature window where this effect takes place. Moreover, we suggests that this effect is a general phenomenon in ferrimagnetic thin films which may also contribute to the understanding of the mechanism behind the all optical switching effect.

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Section: Resultssupporting

confidence: 88%

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

Luo

Ryll

Back

et al. 2019

Sci Rep

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“…In Table 1 we can see that the Dy sublattice shows a lower magnetic moment at T=270K (m= -4.12 ± 0.21 µ B /at) than at T=150K (m=+6.64± 0.33 µ B /at) whereas the magnetic moment of Co does not change within the error bars. The quantitative magnetic moments measured for Co and Dy, as well as their thermal dependences, are consistent with experimental values obtained for similar alloys [46,54]. At T=270K (compared to 150 K) the low Dy M 5 XMCD signal results from the large thermal fluctuations affecting the Zeemann levels.…”

Section: Magnetic Propertiessupporting

confidence: 87%

Element-resolved ultrafast demagnetization rates in ferrimagnetic CoDy

et al. 2017

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Femtosecond laser induced ultrafast magnetization dynamics have been studied in multisublattice CoxDy1-x alloys. By performing element and time-resolved X-ray spectroscopy, we distinguish the ultrafast quenching of Co3d and Dy4f magnetic order when the initial temperatures are below (T=150K) or above (T=270K) the temperature of magnetic compensation (Tcomp). In accordance with former element-resolved investigations and theoretical calculations, we observe different dynamics for Co3d and Dy4f spins. In addition we observe that, for a given laser fluence, the demagnetization amplitudes and demagnetization times are not affected by the existence of a temperature of magnetic compensation. However, our experiment reveals a twofold increase of the ultrafast demagnetization rates for the Dy sublattice at low temperature. In parallel, we measure a constant demagnetization rate of the Co3d sublattice above and below Tcomp. This intriguing difference between the Dy4f and Co3d sublattices calls for further theoretical and experimental investigations.Comment: 6 Figure, 2 Table

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“…We use the following exchange parameters for the interaction between spins located on the same sublattice A/B, J AA = 16 meV, J BB = 0.5 meV, and between spins on different sublattices, J AB = −6 meV. These values are characteristic for ferrimagnetic RE-transition metal (TM) alloys [59], which are testbed materials in the field of ultrafast spin dynamics [13][14][15][16][17], and are receiving an increasing attention in the field of spintronics [54].…”

Section: A Atomistic Spin Modelmentioning

confidence: 99%

Unveiling domain wall dynamics of ferrimagnets in thermal magnon currents: Competition of angular momentum transfer and entropic torque

Donges

Grimm

Jakobs

et al. 2020

Phys. Rev. Research

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Control of magnetic domain wall motion holds promise for efficient manipulation and transfer of magnetically stored information. Thermal magnon currents, generated by temperature gradients, can be used to move magnetic textures, from domain walls, to magnetic vortices and skyrmions. In the last years, theoretical studies have centered in ferro-and antiferromagnetic spin structures, where domain walls always move towards the hotter end of the thermal gradient. Here we perform numerical studies using atomistic spin dynamics simulations and complementary analytical calculations to derive an equation of motion for the domain wall velocity. We demonstrate that in ferrimagnets, domain wall motion under thermal magnon currents shows a much richer dynamics. Below the Walker breakdown, we find that the temperature gradient always pulls the domain wall towards the hot end by minimizating its free energy, in agreement with the observations for ferro-and antiferromagnets in the same regime. Above Walker breakdown, the ferrimagnetic domain wall can show the opposite, counterintuitive behavior of moving towards the cold end. We show that in this case, the motion to the hotter or the colder ends is driven by angular momentum transfer and therefore strongly related to the angular momentum compensation temperature, a unique property of ferrimagnets where the intrinsic angular momentum of the ferrimagnet is zero while the sublattice angular momentum remains finite. In particular, we find that below the compensation temperature the wall moves towards the cold end, whereas above it, towards the hot end. Moreover, we find that for ferrimagnets, there is a torque compensation temperature at which the domain wall dynamics shows similar characteristics to antiferromagnets, that is, quasi-inertia-free motion and the absence of Walker breakdown. This finding opens the door for fast control of magnetic domains as given by the antiferromagnetic character while conserving the advantage of ferromagnets in terms of measuring and control by conventional means such as magnetic fields. arXiv:1911.05393v1 [cond-mat.mtrl-sci]

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

Cited by 21 publications

References 51 publications

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

X-ray magnetic linear dichroism as a probe for non-collinear magnetic state in ferrimagnetic single layer exchange bias systems

Element-resolved ultrafast demagnetization rates in ferrimagnetic CoDy

Unveiling domain wall dynamics of ferrimagnets in thermal magnon currents: Competition of angular momentum transfer and entropic torque

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