Bias voltage and temperature dependence of magneto-electric properties in double-barrier magnetic tunnel junction with amorphous Co-Fe-B electrodes

Abstract

Bias voltage and temperature dependence of magneto-electric properties in double-barrier magnetic tunnel junctions(DBMTJs) with a structure of [IrMn/CoFe/Ru/CoFeB]/Al-O/CoFeB/Al-O/[CoFeB/Ru/CoFe/IrMn], have been investigated. The DBMTJs show a large tunnel magnetoresistance (TMR) ratio of up to 57.6%, a high V1/2 value of 1.26 V and small switching field Hc of 9.5 Oe at room temperature (RT). The TMR reaches the maximum at 30 K, about 89.0%, and decreases slightly from 30 to 4.2 K. A novel zero-bias anomaly (ZBA) in the P state is found and is temperature dependent, more sharply at low temperature, whereas a normal ZBA exists in the AP state. These effects are ascribed to magnon-, phonon- and impurity-assisted tunneling, and variation of density of states. The DBMTJ with a large TMR ratio, a high V1/2, and small switching field Hc is promising for developing the future spin electronic devices.