Abstract:

Recent experiments [1] evidence the emergence of a metallic phase with a high carrier mobility at the interface of some insulating oxides such as LaTiO3 /SrTiO3 or LaAlO3 /SrTiO3. As demon- strated experimentally [2], this new type of two-dimensional electron gas (2DEG) can be laterally confined and patterned to achieve nanometer-size tunnel junctions and to exploit these structure as field-effect transistors. Exciting applications in the field of spintronic are expected when spiral multiferroic oxides are utilized, such as RMnO3 (R=Tb, Dy, Gd) [3]. In this presentation we will discuss how the magnetoelectric coupling [4] can be exploited to functionalize the 2DEG at the interface of these compounds for spintronic applications. In particular, an electrically controllable pure spin current can be generated and the principle of a spin-field-effect transistor and flash- memory device are demonstrated [5]. We also discuss the magneto and thermal transport through in these systems [6] and in tunnel junctions involving multiferroic spacers and demonstrate the existence of anisotropic tunnel magnetoresistance [7] that can be controlled by an applied electric field with a strength in the range of several keV/cm.
[1] A. Ohtomo, and H. Y. Hwang Nature 427, 423 (2004); 441, 120 (2006); A. Ohtomo, et al. ibid. 419, 378 (2002); S. Thiel, G. Hammerl, A. Schmehl, C. W. Schneider, and J. Mannhart Science 313, 1942 (2006).
[2] C. Cen, S. Thiel, J. Mannhart, and J. Levy Science 323, 1026 (2009); E. Singh-Bhalla et al. Nature Phys. 7, 80 (2011).
[3] Mannhart, et al. MRS Bull. 33, 1027 (2008).
[4] H. Katsura, N. Nagaosa, and A. V. Balatsky Phys. Rev. Lett. 95, 057205 (2005); C.L. Jia, J. Berakdar Euro.Phys.Lett. 85, 57004 (2009).
[5] C.L. Jia, J. Berakdar Appl. Phys. Lett. 95, 012105 (2009); Phys. Rev. B 80, 014432 (2009).
[6] C.L. Jia, J. Berakdar Appl. Phys. Lett. 98, 042110 (2011); Phys. Rev. B 83, 045309 (2011).
[7] C.L. Jia, J. Berakdar Phys. Rev. B 81, 052406 (2010).
 
 
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