An Extremely Long Range Exchange Coupling In Crte/Znte/Mnte Trilayer

We present the results on the exchange coupling in the zinc-blende CrTe/spacer/MnTe structure with ZnTe acting as a spacer layer (SL). The magnetic hysteresis (M-H) loops show significant shifts in both horizontal and vertical directions. A nonmonotonic variation of the exchange bias field (H(E)) and coercivity (H(C)) with the SL thickness is observed. The Curie temperature decreases as the SL thickness increases. The maximum of H(E) and H(C) values occur at a SL thickness of 12 ML (monolayer). Strikingly, the exchange coupling remains noticeable even the thickness of SL reaches 24 ML. The exchange bias field and vertical shift are discussed on the basis of frozen ferromagnetic moment model. (C) 2010 American Institute of Physics. [doi:10.1063/1.3352578]