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Ferrimagnetic Tb-Fe based heterostructures: Intriguing properties and applications

Tuesday, July 16, 2019 - 11:00
Place: 
nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
Who: 
Manfred Albrecht, University of Augsburg, Germany
Source Name: 
nanoGUNE

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

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