Title :
Negative TMR in magnetic tunneling junctions with Zr oxide barrier
Author :
Moriyama, T. ; Xiang, X.H. ; Wang, W. ; Li, Fei-fei ; Zhu, T. ; Du, J. ; Ming-wen Xiao ; Li, Zheng-Zhony ; An Hu ; Xiao, John Q.
Author_Institution :
Dept. of Phys. & Astron., Delaware Univ., Newark, DE, USA
Abstract :
The magnetic tunnel junctions (MTJs) were prepared on Si [001] by using magnetron sputtering system. The structures of the MTJs are Si/FeNi/Cu/FeMn/Co/barrier/Co/Cu were the barrier are hybrids: AlOx/ZrOx and ZrOx/AlOx. AlOx as a barrier was also studied for comparison. Negative tunneling magnetoresistance (TMR) was observed in MTJs using hybrid barrier. The TMR shows a strong asymmetric bias dependence and changes from 8% at around zero bias to -4% at a high bias. The negative TMR at high bias is due to not only the energy dependence of spin-DOS but also the barrier shape of the MTJs. The mechanism for the negative TMR at high bias is different from that responsible for the inverse TMR in low bias range.
Keywords :
aluminium compounds; cobalt; copper; iron alloys; manganese alloys; negative resistance; nickel alloys; sputter deposition; tunnelling magnetoresistance; zirconium compounds; Si-FeNi-Cu-FeMn-Co-AlOx-Co-Cu; Si-FeNi-Cu-FeMn-Co-AlOx-ZrOx-Co-Cu; Si-FeNi-Cu-FeMn-Co-ZrOx-AlOx-Co-Cu; asymmetric bias dependence; barrier shape; hybrid barrier; magnetic tunneling junctions; magnetron sputtering system; negative TMR; negative tunneling magnetoresistance; spin-DOS; Electrodes; Laboratories; Magnetic field measurement; Magnetic tunneling; Oxidation; Physics; Shape; Tunneling magnetoresistance; Voltage; Zirconium;
Conference_Titel :
Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International
Print_ISBN :
0-7803-9009-1
DOI :
10.1109/INTMAG.2005.1464433
