Positive MR and Large Temperature-Field Sensitivity in Manganite Based Heterostructures

Studies on the ZnO/La0.5Pr0.2Sr0.3MnO3 (LPSMO)/SrNb0.002Ti0.998O3 (SNTO) heterostructure having varying thickness of p-type LPSMO (100 nm - LP1) and (200 nm - LP2) manganite are carried out. ZnO/LPSMO (n-p) and LPSMO/SNTO (p-n) junctions of both the heterostructures exhibit good rectifying behavior in a wide range of temperature and applied field. Forward and reverse bias characteristics of both the junctions of heterostructures show opposite behavior. The observation of negative magnetoresistance (MR) at 5 K and positive MR at 300 K, in both the heterostructures, has been explained in the context of interface region effects and filling of energy bands of LPSMO manganite. Further, at high temperature, the heterostructures exhibit large temperature (46%K−1) and field (40%T−1) sensitivities. Dependence of transport, magnetotransport, I-V and sensing properties of the heterostructures, on the temperature, field and film thicknesses have been discussed in this communication.