We report the I–V characteristics and the magnetoresistance (MR) behavior of trilayered ZnO (n) (50 nm) / La0.7Sr0.3MnO3 (LSMO) (p) (100 nm) / SrNb0.2Ti0.8O3 (SNTO) (n) manganite based thin film device grown using Pulsed Laser Deposition (PLD) technique. The LSMO/SNTO and ZnO/LSMO junction diodes exhibit good rectifying behavior in the temperature range 5–300 K. The observed decrease in the values of saturation voltage (VC) with increase in temperature has been explained on the basis of band structure of the p‐type LSMO manganite. In addition, with increase in applied field up to 8 T, VC increases at T> 120 K for LSMO/SNTO and at T> 150 K for ZnO/LSMO resulting into positive MR at higher temperatures. The temperature and field dependent variation in MR has been discussed in the context of field induced modification in the band gap, presence of different electronic phases in p‐type LSMO manganite at various temperatures.