Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have bee...Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have been formed by a multi-step deposition and natural oxidization of Mg layer. Mg layer thickness,oxygen flow rate and oxidization time were adjusted and the tunnel magnetoresistance(TMR) ratio of optimal MTJs is over 60% at annealing temperature 385. The(001) MgO crystal structure was obtained when the separation distance between MgO target and substrate is less than 6 cm. The TMR ratio of most MgO based MTJs are over 100% at the separation distance of 5 cm and annealing temperature 340. The TMR ratios of MTJs are almost zero when the separation distance ranges from 6 to 10 cm, due to the amorphous nature of the MgO film.展开更多
基金Natural Science Foundation of Shanghai Science and Technology Commission (grant No. 11ZR1411300)Pujiang Talent Program of Shanghai Science and Technology Commission (grant No. 11PJ1402700) for the financial support
文摘Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have been formed by a multi-step deposition and natural oxidization of Mg layer. Mg layer thickness,oxygen flow rate and oxidization time were adjusted and the tunnel magnetoresistance(TMR) ratio of optimal MTJs is over 60% at annealing temperature 385. The(001) MgO crystal structure was obtained when the separation distance between MgO target and substrate is less than 6 cm. The TMR ratio of most MgO based MTJs are over 100% at the separation distance of 5 cm and annealing temperature 340. The TMR ratios of MTJs are almost zero when the separation distance ranges from 6 to 10 cm, due to the amorphous nature of the MgO film.
