Magnetic and electrical properties of La 0.7Sr 0.3MnO 3- Zn 0.8Co 0.2Al 0.01O junctions on silicon substrates

Abstract

p-n and n-p junctions based on the p -type La0.7 Sr0.3 Mn O3 (LSMO) and the n -type Zn0.8 Co0.2 Al0.01 O (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 ZCAOLSMO 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 (±3 kOe) magnetoresistance (LFMR) value of the ZCAOLSMO 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 ZCAOSi, the LSMO layer has no LFMR property. The LSMOZCAO 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 ZCAOLSMO 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 ZCAOLSMO n-p junction was -15% under forward bias voltages as the external magnetic field varied from 0 to 3 kOe. © 2005 American Institute of Physics.