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Enhancement of Thermopower by Structural Asymmetry in Double-Barrier Tunnel Junctions

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Abstract

Thermopower is studied in double-barrier magnetic tunnel junctions (DBMTJs) with a non-magnetic metal (NM) spacer by considering structural asymmetry—related to the different thicknesses of the MgO insulators—in the linear response regime. Using non-equilibrium Green’s function (NEGF) formalism, it is found that the thermopower is larger in the case with thicker left insulator than the other cases which is related to the voltage drop within the insulator layer. The thermopower has shown its maximum value as large as S = 482μ V/K in the anti-parallel configuration of the magnetizations and T = 300K. Therefore, it is possible to achieve the large thermopower in the thermoelectric devices based on MTJs.

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References

  1. Weller, D., et al.: A HAMR media technology road map to an areal density of 4T b/i n 2. IEEE Trans. Mag. 50, 3100108 (2014)

    Article  Google Scholar 

  2. Walter, M., Walowski, J., Zbarsky, V., Münzenberg, M., Schäfers, M., Ebke, D., Reiss, G., Thomas, A., Peretzki, P., Seibt, M., Moodera, J. S., Czerner, M., Bachmann, M., Heiliger, C.: Seebeck effect in magnetic tunnel junctions. Nature. Mater. 10, 742 (2011)

    Article  ADS  Google Scholar 

  3. Liebing, N., Serrano-Guisan, S., Rott, K., Reiss, G., Langer, J., Ocker, B., Schumacher, H. W.: Tunneling magnetothermopower in magnetic tunnel junction nanopillars. Phys. Rev. Lett. 107, 177201 (2011)

    Article  ADS  Google Scholar 

  4. Lin, W., Hehn, M., Chaput, L., Negulescu, B., Andrieu, S., Montaigne, F., Mangin, S.: Giant spin-dependent thermoelectric effect in magnetic tunnel junctions. Natuer. Commun. 3, 744 (2012)

    Article  ADS  Google Scholar 

  5. Wilczyński, M.: Thermopower, figure of merit and spin-transfer torque induced by the temperature gradient in planar tunnel junctions. J. Phys.: Condens. Matter. 23, 456001 (2011)

    Google Scholar 

  6. Czerner, M., Bachmann, M., Heiliger, C.: Spin caloritronics in magnetic tunnel junctions: Ab initio studies. Phys. Rev. B 83, 132405 (2011)

    Article  ADS  Google Scholar 

  7. Geisler, B., Kratzer, P.: Spincaloric properties of epitaxial CO2MnSi/MgO/CO2 MnSi magnetic tunnel junctions. Phys. Rev. B 92, 144418 (2015)

    Article  ADS  Google Scholar 

  8. Uchida, K., et al.: Observation of the spin Seebeck effect. Nature (London) 455, 778 (2008)

    Article  ADS  Google Scholar 

  9. Wang, S. -Z., Xia, K., Baur, G. E. W.: Thermoelectricity and disorder of FeCo/MgO/FeCo magnetic tunnel junctions. Phys. Rev. B 90, 224406 (2014)

    Article  ADS  Google Scholar 

  10. Zhang, Z. H., Gui, Y. S., Fu, L., Fan, X. L., Cao, J. W., Xue, D. S., Freitas, P. P., Houssameddine, D., Hemour, S., Wu, K., Hu, C.-M.: Seebeck rectification enabled by intrinsic thermoelectrical coupling in magnetic tunneling junctions. Phys. Rev. Lett. 109, 037206 (2012)

    Article  ADS  Google Scholar 

  11. Boehnke, A., Walter, M., Roschewsky, N., Eggebrecht, T., Drewello, V., Rott, K., Munzenberg, M., Thomas, A., Reiss, G.: Time-resolved measurement of the tunnel magneto-Seebeck effect in a single magnetic tunnel junction. Rev. Sci. Instrum. 84, 063905 (2013)

    Article  ADS  Google Scholar 

  12. Teixeira, J. M., Costa, J. D., Ventura, J., Fernandez-Garcia, M. P., Azevedo, J., Araujo, J. P., Sousa, J. B., Wisniowski, P., Cardoso, S., Freitas, P. P.: Giant intrinsic thermomagnetic effects in thin MgO magnetic tunnel junctions. Appl. Phys. Lett. 102, 212413 (2013)

    Article  ADS  Google Scholar 

  13. Wilczyn’ski, M.: Thermopower in double planar tunnel junctions with ferromagnetic barriers and nonmagnetic electrodes. J. Magn. Magn. Mater. 421, 418 (2017)

    Article  ADS  Google Scholar 

  14. Jia, X., Wang, S., Qin, M.: Seeking large thermoelectric effects in MgO-based tunnel junctions. New J. Phys. 18, 063028 (2016)

    Article  ADS  Google Scholar 

  15. Datta, S.: Quantum transport: atom to transistor. Cambridge University Press, New York (2005)

    Book  MATH  Google Scholar 

  16. Datta, D., Behin-Aein, B., Salahuddin, S., Datta, S.: Voltage asymmetry of spin transfer torques. IEEE Trans. Nano. 11, 261 (2012)

    Article  Google Scholar 

  17. Daqiq, R., Ghobadi, N.: Resonant spin-transfer torque in asymmetric double barrier magnetic tunnel junctions (MTJs). Superlattices and Microstruct. 102, 417 (2017)

    Article  ADS  Google Scholar 

  18. Sivan, U., Imry, Y.: Multichannel Landauer formula for thermoelectric transport with application to thermopower near the mobility edge. Phys. Rev. B 33, 551 (1986)

    Article  ADS  Google Scholar 

  19. Proetto, C. R.: Thermopower oscillations of a quantum-point contact. Phys. Rev. B 44, 9096 (1991)

    Article  ADS  Google Scholar 

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Authors and Affiliations

  1. Department of Physics, Malayer University, Malayer, Iran

    Reza Daqiq

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  1. Reza Daqiq
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Correspondence to Reza Daqiq.

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Daqiq, R. Enhancement of Thermopower by Structural Asymmetry in Double-Barrier Tunnel Junctions. J Supercond Nov Magn 31, 313–316 (2018). https://doi.org/10.1007/s10948-017-4212-4

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  • DOI: https://doi.org/10.1007/s10948-017-4212-4

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