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

fYear

2005

fDate

4-8 April 2005

Firstpage

1989

Lastpage

1990

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: AlO_x/ZrO_x and ZrO_x/AlO_x. AlO_x 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-AlO_x-Co-Cu; Si-FeNi-Cu-FeMn-Co-AlO_x-ZrO_x-Co-Cu; Si-FeNi-Cu-FeMn-Co-ZrO_x-AlO_x-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;

fLanguage

English

Publisher

ieee

Conference_Titel

Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International

Print_ISBN

0-7803-9009-1

Type

conf

DOI

10.1109/INTMAG.2005.1464433

Filename

1464433