Ferrimagnetic Tb-Fe based heterostructures: Intriguing properties and applications
CIC nanoGUNE Seminars
- Speaker
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Manfred Albrecht, University of Augsburg, Germany
- When
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2019/07/16
13:00 - Place
- nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
- Add to calendar
-
iCal
Ultrafast magnetization switching is at the heart of both modern information
storage technology and fundamental science. In this regard, it was recently
observed that ultra-fast magnetization reversal processes can be induced by
circularly polarized laser pulses in ferrimagnetic GdFeCo alloy thin films
[1]. This novel observation resulted in a broad range of exciting and
challenging fundamental questions, and may enable new applications based on
ultra-fast spintronics. An overview of our activities on all-optical switching
in ferrimagnetic TbFe films [2-4] will be pre-sented.
In a further study, we tried to combine this AOS property with magnetic thin
films with high magnetic anisotropy such as L10 ordered FePt, which are in
high demand for ultra high-density magnetic recording. In this attempt FePt-Tb
alloy thin films were investigated. Another intriguing property of
ferrimagnetic/ferromagnetic heterostructures is the exchange bias effect.
Here, the dependence of the interfacial exchange coupling on the stoichiometry
of the fer-rimagnetic TbFe layer was analyzed. A large exchange-bias field up
to several Tesla is found to be accompanied by an interfacial domain wall as
probed by element specific x-ray magnetic cir-cular dichroism absorption
measurements [5]. In addition, unexpected results on the exchange bias effect
in two coupled ferrimagnetic TbFe layers will be shown [6]. Recently, a new
type of THz emitter has been discovered [7], which is based on the inverse
spin Hall effect. These “spintronic†THz emitters can generate a high THz
intensity and are broadband up to 30 THz. Here I will show results on the THz
emission of a layered spintronic system based on Pt and (TbxFe1−x) alloys
for the entire range of Tb content (0 ≤ x ≤ 1) under different external
applied magnetic fields [8].
[1] C. D. Stanciu et al., Phys. Rev. Lett. 99, 047601 (2007)
[2] A. Hassdenteufel et al., Adv. Mater. 25, 3122 (2013)
[3] A. Hassdenteufel et al., Phys. Rev. B 91, 104431 (2015)
[4] B. Hebler et al., Frontiers in Materials 3, 8 (2016)
[5] C. Schubert et al., Phys. Rev. B 87, 054415 (2013)
[6] B. Hebler et al., Phys. Rev. B 95, 104410 (2017)
[7] T. Kampfrath et al., Nat. Nanotechnol. 8, 256 (2013)
[8] R. Schneider et al., ACS Photonics 5, 3936 (2018)
**Host: **A. Berger