Optical and Magneto-Tunable Electrical Transport Across La0.7Sr0.3 MnO3, Zn0.3 Ni0.7 Fe2O4/CuPc Hybrid Interfaces

Light and magnetic field-dependent carrier transport properties of ITO/ La 0.7 Sr 0.3 MnO 3 (LSMO)/CuPc/Au (Device A) and p-Si/ Zn 0.3 Ni 0.7 Fe 2 O4 (ZNFO)/CuPc/Au (Device B) heterostructure devices are investigated. Current (I)-voltage (V) response indicates efficient carrier tunneling through LSMO/CuPc and ZNFO/CuPc interface of the respective devices. Carrier injection ( EF -HOMO) with tunneling may be present at low bias for Device B, due to small band offset thereby leading to small nonlinearity in I-V curves. Light-dependent measurements indicate efficient photocurrent generation aided by Frankel exciton generation at CuPc bulk and subsequent separation at LSMO/CuPc interface for Device A. Magnetic field-dependent scattering both at LSMO/CuPc interface and LSMO bulk has been observed from impedance measurements. Positive magnetoresistance at low bias indicates high degree of positive spin polarization within ZNFO/CuPc interface, at room temperature. ZNFO/CuPc interface resistance reduces with field due to enhanced tunneling owing to reduction in depth of defect states. However, increase in ZNFO bulk resistance has been attributed to increase in interfacial polarization with magnetic field.