Abstract.
A magnetic tunnel junction consists of two ferromagnetic conducting electrodes separated by an insulating thin layer. The performance of such a system strikingly depends on the last conducting atomic layers in contact with the insulator. Consequently, the present paper reports a nanoscale electron energy loss spectroscopy (EELS) study, which has been performed across a couple of La0.66Sr0.33MnO3,/SrTiO3/La0.66Sr0.33MnO3 tunnel junctions with different barrier thickness es (1.5 nm and 5 nm respectively). It aims at determining not only the chemical composition in the interface areas, but also the effect of the neighbouring atoms on their electronic structure. Using recent improvements in the STEM-EELS data acquisition and processing techniques (systematic use of spectrum-line and spectrum-image modes, multivariate statistical analysis, 2D energy deconvolution schemes, etc.), the local chemical information is better extracted with shorter acquisition times, while the large increase of the data set contributes to validate the results. Within the accuracy level of these measurements, the elemental composition of the different phases remains stable up to the interfaces with no evidence of extra doping. Furthermore, weak changes on the Mn-2p edge fine structures (weak shift to lower energy loss values and extra splitting on the top of the Mn L3 line are observed on all the interfaces. They are interpreted as a consequence of a slight reduction of the local Mn valence likely accompanied by a strain induced change in local symmetry. The discussion is focussed on all spectral changes identified at a (sub)nanometer scale and their potential effects on the degradation of magnetic and transport properties measured, close to room temperature, at a macroscopic level.
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References
H.L. Ju, H.-C. Sohn, K.M. Krishnan, Phys. Rev. Lett. 79, 3230 (1997)
T. Saitoh, A.E. Bocquet, T. Mizokawa, H. Namatame, A. Fujimori, Phys. Rev. B 51, 13942 (1995)
C. Zener, Phys. Rev. 82, 403 (1951)
P.G. de Gennes, Phys. Rev. B 118, 141 (1960)
J.-M De Teresa, A. Barthélémy, A. Fert, J.-P. Contour, F. Montaigne, P. Seneor, Science 286, 507 (1999)
A. Fert, , Materials. Sci. Engineering B 84, 1 (2001)
J.S. Noh, T.K. Nath, C.B. Eom, J.Z. Sun, W. Tian, X.Q. Pan, Appl. Phys. Lett. 79, 233 (2001)
Y. Lu, X.W. Li, G.Q. Gong, Gang Xiao, A. Guptaz, P. Lecoeur, J.Z. Sun, Y.Y. Wang, V.P. Dravid, Phys. Rev. B 54, 8357 (1996)
M. Viret, M. Drouet, J.-P. Contour, J. Nassar, C. Fermon, A. Fert, Europhys. Lett. 39, 545 (1997)
J. Nassar, M. Viret, M. Drouet, J.-P. Contour, C. Fermon, A. Fert, Mat. Res. Soc. Symp. Proc. 494, 231 (1998)
E. Favre-Nicolin, L. Ranno, C. Dubourdieu, M. Rosina, Thin Solid Films. 400, 165 (2001)
M. Viret, L. Ranno, J.M.D. Coey, J. Appl. Phys. 81, 4964 (1997)
M. Bibes, Ll. Balcells, S. Valencia, S. Sena, B. Martinez, J. Fontcuberta, J. of Appl. Phys. 89, 6686 (2001)
M. Bibes, M.J. Casanove, Ll. Balcells, S. Valencia, B. Martinez, J.C. Ousset, J. Fontcuberta, Appl. Surf. Sci. 188, 202 (2002)
M. Viret, J. Nassar, M. Drouet, J.-P. Contour, C. Fermon, A. Fert, J. Magn. Magn. Mater. 198-199, 1 (1999)
M. Izumi, Y. Konishi, T. Nishihara, S. Hayashi, M. Shinohara, M. Kawasaki, Y. Tokura, Appl. Phys. Lett. 73, 2497 (1998)
R. Bertacco, M. Portalupi, M. Marcon, L. Duo, F. Ciccacci, M. Bowen, J.-P. Contour, A. Barthélémy, J. Magn. Magn. Mater. 242, 710 (2002)
R. Bertacco, J.-P. Contour, A. Barthélémy, J. Olivier, Surf. Sci. 511, 366 (2002)
H.Y. Hwang, S.W. Cheong, N.P. Ong, B. Batlogg, Phys. Rev. Lett. 77, 2041 (1996)
J.M. Teresa, A. Barthélémy, A. Fert, J.-P. Contour, R. Lyonnet, F. Montaigne, P. Seneor, A. Vaurès, Phys. Rev. Lett. 82, 4288 (1999)
J.-L. Maurice, R. Lyonnet, J.-P. Contour, J. Magn. Magn. Mater. 211, 91 (2000)
F. Pailloux, R. Lyonnet, J.-L. Maurice, J.-P. Contour, Appl. Surf. Sci. 177, 263 (2001)
J.-L. Maurice, F. Pailloux, A. Barthélémy, A. Rocher, O. Durand, R. Lyonnet, J.-P. Contour, Appl. Surf. Sci. 188, 176 (2002)
O.I. Lebedev, J. Verbeeck, G. Van Tendeloo, S. Amelinckx, F.S. Razavi, H.-U. Habermeier, Phil. Mag. A 81, 2865 (2001)
F. Pailloux, D. Imhoff, T. Sikora, A. Barthélémy. J.-L. Maurice, J.-P. Contour, C. Colliex, A. Fert, Phys. Rev. B 66, 14417 (2002)
J. Benedict, R. Anderson, S. Klepeis, M. Chaker, Mater. Res. Soc. Symp. Proc. 199, 189 (1990)
P. Stadelman, Ultramicroscopy 21, 131 (1987)
J.-L. Maurice, F. Pailloux, D. Imhoff, N. Bonnet, L. Samet, A. Barthélémy, J.-P. Contour, C. Colliex, A. Fert (accepted, Eur. Phys. J AP)
J.-L. Maurice, F. Pailloux, A. Barthélémy, O. Durand, D. Imhoff, R. Lyonnet, A. Rocher, J.-P. Contour (accepted, Phil. Mag.)
Spectrometer modified at Laboratoire "Physique des Solides" in Orsay by Marcel Tencé and Paul Ballongue
C. Jeanguillaume, C. Colliex, Ultramicroscopy 28, 252 (1989)
R.F. Egerton, Electron Energy Loss Spectroscopy in Electron Microscope (Plenum Press NY, 1986)
N. Bonnet, N. Brun, C. Colliex, Ultramicroscopy 77, 97 (1999)
P. Trebbia, N. Bonnet, Ultramicroscopy 34, 165 (1990)
A. Gloter, A. Douiri, M. Tencé, C. Colliex, Ultramicroscopy 96 (3-4), 385 (2003)
T. Manoubi, M. Tencé, M.G. Walls, C. Colliex, Microsc. Microanal. Microstruct. 1, 23 (1990).
H. Kurata, C. Colliex, Phys. Rev. B 48, 2102 (1993)
J. Verbeek, O.I. Lebedev, G. Van Tendeloo, J. Silcox, B. Mercey, M. Hervieu, A.M. Haghin-Gosnet, Appl. Phys. Lett. 79, 2037 (2001)
J. Verbeeck, O.I. Lebedev, G. Van Tendeloo, B. Mercey, Phys. Rev. B 66, 184426 (2002)
C. Prunier-Mory, Ph.D. Thesis, Paris-Sud Univ. (1985)
M. Abbate, F.M.F. de Groot, J.C. Fuggle, A. Fujimori, O. Strebel, F. Lopez, M. Domke, G. Kaindl, G.A. Sawatzky, M. Takano, Y. Takeda, H. Eisaki, S. Uchida, Phys. Rev. B 46, 4511 (1992)
E. Pellegrin, L.H. Tjeng, F.M.F. de Groot, R. Hesper, G.A. Sawatzky, Y. Moritomo, Y. Tokura, J. Electron Spectroscopy Related Phenomena 86, 115 (1997)
Z.L. Wang, J.Z. Yin, Y.D. Zhang, W.D. Mo, J. Phys. Chem B 101, 6793 (1997)
F.M.F. de Groot, Ph.D. Thesis, University of Nijmegen, Toernooveld, 6525 ED Nijmegen, The Netherlands (1991)
Shang-Di Mo, W.Y. Ching, M.F. Chisholm, G. Dusher, Phys. Rev. B 60, 2416 (1999)
M. Grioni, M.T. Czyzyk, F.M.F. de Groot, J.C. Fuggle, B.E. Watts, Phys. Rev. B 39, 4886, (1990)
H. Kurata, E. Lefevre, C. Colliex, R. Brydson, Phys. Rev. B 47, 13763 (1993)
H.A. Jahn, E. Teller, Proc. Roy. Soc. (London) A 164, 117 (1938)
E. Warren, W.E. Picket, D.J. Singh, Phys. Rev. B 53, 1146 (1996)
A. Chainani, M. Mathew, D.D. Sarma, Phys. Rev. B 47, 15397 (1993)
P.E. Batson, N. Delby, O.L. Krivanek, Nature 418, 617 (2002)
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Received: 14 April 2003, Published online: 4 August 2003
PACS:
75.45.+j Macroscopic quantum phenomena in magnetic systems - 82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.) - 68.37.Lp Transmission electron microscopy (TEM) (including STEM, HRTEM, etc.) - 85.30.Mn Junction breakdown and tunneling devices (including resonance tunneling devices)
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Samet, L., Imhoff, D., Maurice, JL. et al. EELS study of interfaces in magnetoresistive LSMO/STO/LSMO tunnel junctions. Eur. Phys. J. B 34, 179–192 (2003). https://doi.org/10.1140/epjb/e2003-00210-8
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DOI: https://doi.org/10.1140/epjb/e2003-00210-8