Instytut Fizyki Molekularnej Polskiej Akademii Nauk

Seminaria

Wydarzenia w wrześniu 2018:

SEMINARIUM INSTYTUTOWE

Dnia: 19.09.2018 roku (środa)
o godzinie 13:00 w auli

referat pt.:

Broadband dielectric spectroscopy (BDS) of high-permittivity,high-loss dielectrics and inhomogeneous conductors

wygłosi

dr Viktor Bovtun

Institute of Physics, Czech Academy of Sciences, Praha


SEMINARIUM INSTYTUTOWE

Dnia: 12.09.2018 roku (środa)
o godzinie 13:00 w auli

referat pt.:

Spin-orbit technologies: memory switching to THz generation

wygłosi

prof. Hyunsoo Yang

Department of Electrical and Computer Engineering, National University of Singapore

Current induced spin-orbit torques (SOTs) provide a new way to manipulate the magnetization. We first try to understand various spin textures. In order to probe spin textures, we utilize the bilinear magnetoelectric resistance [1], photovoltage microscopy [2] for topological insulators, and Lorentz transmission electron microscopy [3] for imaging of chiral spin textures, skyrmions in an exchange-coupled Co/Pd multilayer.
We then utilize those spin textures for magnetization switching. We find that a full sign reversal of SOTs occurs as the oxygen bonding increases in Pt/CoFeB/MgO, which evidences an interfacial SOT mechanism [4]. We show much enhanced current induced SOTs from Co/Pd multilayers [5], ferrimagnetic CoGd systems [6], a topological insulator Bi2Se3 [7,8] as well as an oxide heterostructure SrTiO3/LaAlO3[9,10], which generate strong spin currents to switch the magnetization. In order to understand detailed switching SOT switching mechanism, time resolved SOT spin dynamics is probed [11], and oscillatory SOT switching induced by field-like torques is measured [12]. We propose a field-free SOT switching scheme using one domain wall motion in an anti-notch structure [13]. Finally, we discuss the generation of THz for heavy metal/ferromagnet structures using SOTs [14,15].

 

1. P. He et al., Nat. Phys. 14, 495 (2018)

2. Y. Liu et al., Nat. Commun. 9, 2492 (2018)

3. S. Pollard et al., Nat. Commun. 8, 14761 (2017)

4. X. Qiu et al., Nat. Nanotechnol. 10, 333 (2015)

5. M. Jamali et al., Phys. Rev. Lett. 111, 246602 (2013)

6. R. Mishra et al., Phys. Rev. Lett. 118, 167201 (2017)

7. Y. Wang et al., Phys. Rev. Lett. 114, 257202 (2015)

8. Y. Wang et al., Nat. Commun. 8, 1364 (2017)

9. K. Narayanapillai et al., Appl. Phys. Lett. 105, 162405 (2014)

10. Y. Wang et al., Nano Lett. 17, 7659 (2017)

11. J. Yoon et al., Sci. Adv. 3, e1603099 (2017)

12. J. Lee et al., Commun. Phys. 1, 2 (2018)

13. J. Lee et al., Nano Lett. 18, 4669 (2018)

14. Y. Wu et al., Adv. Mat. 29, 1603031 (2017)

15. M. Chen et al., Adv. Opt. Mat. doi.org/10.1002/adom.201800430 (2018)

Tło strony

Żel fizyczny utworzony przez żelator methyl-4,6-O-(p-nitrobenzylidene)-α-D-glukopyranozę z butanolem w stężeniu 2%, obraz z polaryzacyjnego mikroskopu optycznego