Magnetic and electrical properties of La0.7Sr0.3MnO3–Zn0.8Co0.2Al0.01O junctions on silicon substrates

Abstract

p - n and n-p junctions based on the p-type La0.7Sr0.3MnO3 (LSMO) and the n-type Zn0.8Co0.2Al0.01O (ZCAO) have been fabricated on silicon substrates via pulsed laser deposition. Both LSMO and ZCAO thin layers deposited on Si had good remanent magnetic characteristics at room temperature. The metal-semiconductor transition temperature (Tp) of the ZCAO∕LSMO n-p junction is lower than that of the pure LSMO layer, which is due to the influence of the top ZCAO layer. The low-field (±3kOe) magnetoresistance (LFMR) value of the ZCAO∕LSMO n-p junction is about −15% at 80 K, which is lower than that of the pure LSMO layer on Si (−21%). As deposited on top of ZCAO∕Si, the LSMO layer has no LFMR property. The LSMO∕ZCAO p-n junction has good current flow versus voltage (I–V) property with a threshold voltage of about 1.5 V at 80–300 K, which is very similar to normal Si-based p-n diode. Its I–V characteristics cannot be modulated by low external magnetic fields. However, the ZCAO∕LSMO n-p junction demonstrated a nonlinear I–V behavior, and its current flow can be modulated by low external magnetic fields. The resistance variation of the ZCAO∕LSMO n-p junction was −15% under forward bias voltages as the external magnetic field varied from 0 to 3 kOe.