Trap-Assisted Tunneling Resistance Switching Effect In Ceo2/La-0.7(Sr0.1ca0.9)(0.3)Mno3 Heterostructure

We reported the resistance switching (RS) behavior in the epitaxially grown CeO2/La-0.7(Sr0.1Ca0.9)(0.3)MnO3 (CeO2/LSCMO) heterojunctions on SrTiO3 substrate. The CeO2/LSCMO device displayed improved switching characteristics as compared to that of metal/manganite device. The switching threshold voltage showed a strong dependence on the thickness of the CeO2 layer, where a minimum/maximum thickness was required for the appearance of the resistance switching. Both set and reset threshold voltages increase with the increase of the CeO2 layer thickness due to the trap-assisted electron tunneling effect. In the meantime, the defects or vacancies in the CeO2 films, in particular, the concentration of the defects or vacancies in the interface between CeO2 and LSCMO, have a significant impact on the switching effect. These results suggest that the electron tunneling accompanied by a trapping/detrapping process at the interface is likely responsible for the RS effect in the insulator/manganite system. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4760221]