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Title: Time resolved spin Seebeck effect experiments

Abstract

In this Letter, we present the results of transient thermopower experiments, performed at room temperature on yttrium iron garnet/platinum bilayers. Upon application of a time-varying thermal gradient, we observe a characteristic low-pass frequency response of the ensuing thermopower voltage with cutoff frequencies of up to 37 MHz. We interpret our results in terms of the spin Seebeck effect, and argue that small wavevector magnons are of minor importance for the spin Seebeck effect in our thin film hybrid structures.

Authors:
; ; ; ; ;  [1];  [1];  [2]; ;  [1];  [3];  [1];  [4];  [3]
  1. Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)
  2. (Netherlands)
  3. (NIM), Munich (Germany)
  4. (Germany)
Publication Date:
OSTI Identifier:
22300199
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 20; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ELECTRIC POTENTIAL; FERRITE GARNETS; LAYERS; MAGNONS; MHZ RANGE; PLATINUM; SEEBECK EFFECT; SPIN; TEMPERATURE GRADIENTS; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; TIME RESOLUTION; TRANSIENTS; YTTRIUM COMPOUNDS

Citation Formats

Roschewsky, Niklas, E-mail: niklas.roschewsky@wmi.badw.de, Schreier, Michael, Schade, Felix, Ganzhorn, Kathrin, Meyer, Sibylle, Geprägs, Stephan, Kamra, Akashdeep, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Huebl, Hans, Goennenwein, Sebastian T. B., Nanosystems Initiative Munich, Gross, Rudolf, Physik-Department, Technische Universität München, Garching, and Nanosystems Initiative Munich. Time resolved spin Seebeck effect experiments. United States: N. p., 2014. Web. doi:10.1063/1.4879462.
Roschewsky, Niklas, E-mail: niklas.roschewsky@wmi.badw.de, Schreier, Michael, Schade, Felix, Ganzhorn, Kathrin, Meyer, Sibylle, Geprägs, Stephan, Kamra, Akashdeep, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Huebl, Hans, Goennenwein, Sebastian T. B., Nanosystems Initiative Munich, Gross, Rudolf, Physik-Department, Technische Universität München, Garching, & Nanosystems Initiative Munich. Time resolved spin Seebeck effect experiments. United States. doi:10.1063/1.4879462.
Roschewsky, Niklas, E-mail: niklas.roschewsky@wmi.badw.de, Schreier, Michael, Schade, Felix, Ganzhorn, Kathrin, Meyer, Sibylle, Geprägs, Stephan, Kamra, Akashdeep, Kavli Institute of Nanoscience, Delft University of Technology, Delft, Huebl, Hans, Goennenwein, Sebastian T. B., Nanosystems Initiative Munich, Gross, Rudolf, Physik-Department, Technische Universität München, Garching, and Nanosystems Initiative Munich. Mon . "Time resolved spin Seebeck effect experiments". United States. doi:10.1063/1.4879462.
@article{osti_22300199,
title = {Time resolved spin Seebeck effect experiments},
author = {Roschewsky, Niklas, E-mail: niklas.roschewsky@wmi.badw.de and Schreier, Michael and Schade, Felix and Ganzhorn, Kathrin and Meyer, Sibylle and Geprägs, Stephan and Kamra, Akashdeep and Kavli Institute of Nanoscience, Delft University of Technology, Delft and Huebl, Hans and Goennenwein, Sebastian T. B. and Nanosystems Initiative Munich and Gross, Rudolf and Physik-Department, Technische Universität München, Garching and Nanosystems Initiative Munich},
abstractNote = {In this Letter, we present the results of transient thermopower experiments, performed at room temperature on yttrium iron garnet/platinum bilayers. Upon application of a time-varying thermal gradient, we observe a characteristic low-pass frequency response of the ensuing thermopower voltage with cutoff frequencies of up to 37 MHz. We interpret our results in terms of the spin Seebeck effect, and argue that small wavevector magnons are of minor importance for the spin Seebeck effect in our thin film hybrid structures.},
doi = {10.1063/1.4879462},
journal = {Applied Physics Letters},
number = 20,
volume = 104,
place = {United States},
year = {Mon May 19 00:00:00 EDT 2014},
month = {Mon May 19 00:00:00 EDT 2014}
}
  • Spin Seebeck effect (SSE) holds promise for new spintronic devices with low-energy consumption. The underlying physics, essential for a further progress, is yet to be fully clarified. This study of the time resolved longitudinal SSE in the magnetic insulator yttrium iron garnet concludes that a substantial contribution to the spin current stems from small wave-vector subthermal exchange magnons. Our finding is in line with the recent experiment by S. R. Boona and J. P. Heremans [Phys. Rev. B 90, 064421 (2014)]. Technically, the spin-current dynamics is treated based on the Landau-Lifshitz-Gilbert equation also including magnons back-action on thermal bath, whilemore » the formation of the time dependent thermal gradient is described self-consistently via the heat equation coupled to the magnetization dynamics.« less
  • We propose a high-efficiency thermospin device constructed by a carbon atomic chain sandwiched between two ferromagnetic (FM) zigzag graphene nanoribbon electrodes. In the low-temperature regime, the magnitude of the spin figure of merit is nearly equal to that of the corresponding charge figure of merit. This is attributed to the appearances of spin-resolved Fano resonances in the linear conductance spectrum resulting from the quantum interference effects between the localized states and the expanded states. The spin-dependent Seebeck effect is obviously enhanced near these Fano resonances with the same spin index; meanwhile, the Seebeck effect of the other spin component hasmore » a smaller value due to the smooth changing of the linear conductance with the spin index. Thus, a large spin Seebeck effect is achieved, and the magnitude of the spin figure of merit can reach 1.2 at T = 25 K. Our results indicate that the FM graphene-carbon-chain junctions can be used to design the high-efficiency thermospin devices.« less
  • We experimentally observed the inverse spin Hall effect (ISHE) of ferromagnetic FePt alloys. Spin Seebeck effect due to the temperature gradient generated the spin current (J{sub s}) in the FePt|Y{sub 3}Fe{sub 5}O{sub 12} (YIG) structure, and J{sub s} was injected from YIG to FePt and converted to the charge current through ISHE of FePt. The significant difference in magnetization switching fields for FePt and YIG led to the clear separation of the voltage of ISHE from that of anomalous Nernst effect in FePt. We also investigated the effect of ordering of FePt crystal structure on the magnitude of ISHE voltagemore » in FePt.« less
  • Spin Seebeck effect (SSE) and spin Hall magnetoresistance (SMR) are observed simultaneously in the Pt/Y{sub 3}Fe{sub 5}O{sub 12} hybrid structure when thermal gradient is produced by Joule heating. According to their dependences on applied current, these two effects can be separated. Their dependence on heating power and magnetic field is systematically studied. With the increase of heating power, the SSE enhances linearly, whereas the SMR decreases slowly. The origin of the spin currents is further analyzed. The heating power dependences of the spin currents associated with the SSE and the SMR are found to be different.