Central achievements of the TERAMAG project are as follows. First, new experimental schemes were developed to probe ultrafast spin transport [1-9], magnetoresistive effects [11, 12] at THz frequencies, as well as the coupling between spins and electron-orbital and crystal-lattice subsystems from femtoseconds to microseconds [13, 14].
Second, based on this methodology, new insights into ultrafast spin dynamics were obtained, in particular, into the microscopic steps leading to the spin Seebeck effect [3, 4] and superdiffusive spin transport [5], the temporal structure and intrinsic and extrinsic contributions to the anomalous Hall effect [11] and anisotropic magnetoresistance [12], as well as the energy and angular-momentum equilibration between highly nonthermal and thermal electrons with electron spins in a ferromagnetic metal [13], and between a hot phonon bath and electron spins in a ferrimagnetic insulator [14].
Finally, interesting applications of (1-3) emerged, for instance optically gated switching of magnetoresistive elements [15], THz Néel spin orbit torque [16] and optically driven spintronic THz emitters [1, 17, 18]. The latter have attractive properties, e.g. large bandwidth and efficiency exceeding that of state-of-the-art emitters such as ZnTe and GaP [1, 17, 18], independence of the pump wavelength from the infrared to vacuum-ultraviolet [1, 17, 19, 20], contact-free setting of the THz polarization plane at rates >10 kHz [21], scalability of the emitter, resulting in THz peak fields >1 MV/cm and fluences of ~1 mJ/cm2 [22-24], and amenability to microstructuring, resulting in on-chip applications [25]. The spintronic THz emitters are meanwhile commercially available.
Selected publications of the >40 TERAMAG-related papers, in particular from the last funding period:
[1] Seifert et al., Appl. Phys. Lett. 120, 180401 (2022)
[2] Lu et al., Nanophotonics 11, 2661-2691 (2022)
[3] Seifert et al., Nature Commun. 9, Article number: 2899 (2018)
[4] P. Jiménez-Cavero et al., Phys. Rev B 105, 184408 (2022)
[5] Rouzegar et al.,Phys. Rev. B 106, 144427 (2022)
[6] Wahada et al., Nano Lett. 9, 3539–3544 (2022)
[7] Gueckstock et al., Appl. Phys. Lett. 120, 062408 (2022)
[8] Bierhance et al., Appl. Phys. Lett. 120, 082401 (2022)
[9] Gueckstock et al.,Advanced Materials 2006281 (2021)
[10] Nádvorník et al., Adv. Mater. Interfaces 2201675 (2022)
[11] Seifert et al., Advanced Materials 2007398 (2021)
[12] Nadvorník et al., Phys. Rev. X 11, 021030 (2021)
[13] Chekhov et al., Phys. Rev. X 11, 041055 (2021)
[14] Maehrlein et al., Sci. Adv. 4, eaar5164 (2018)
[15] Heitz et al., Phys. Rev. Appl. 16, 064047 (2021)
[16] Behovits et al., arXiv.2305.03368 (2023)
[17] Fülöp et al., Adv. Opt. Mat. 1900681 (2019)
[18] Seifert et al., Nat. Photon. 10, 483 (2016)
[19] Herapath et al., Appl. Phys. Lett. 114, 041107 (2019)
[20] Ilyakov et al., Optica 9, 545 (2022)
[21] Gueckstock et al., Optica 8, 1013-1019 (2021)
[22] Seifert et al., Appl. Phys. Lett. 110, 252402 (2017)
[23] Vogel et al., Opt. Expr. 30, 20451 (2022)
[24] Rouzegar et al., Phys. Rev. Appl. (in print, 2023)
[25] Hoppe et al., ACS Appl. Nano Mater. 4, 7454-7460 (2021)
[26] Vedmedenko et al., J. Phys. D: Appl. Phys. 53, 453001 (2020)
[27] Leitenstorfer et al., J. Phys. D: Appl. Phys. 56, 223001(2023)
