Magnetoresistance studies on CoAl OX Au and CoAl OX NiAu tunnel structures

• We report on magnetoresistance (MR) studies on CoAl OX Au and CoAl OX NiAu magnetic tunnel junctions. In spite of the fact that the difference between the two samples is merely a 3 nm thick Ni layer, there is a sharp contrast in MR behavior indicating that the electronic structure at the interface between the ferromagnetic electrodes and the insulating barrier dominates the MR signal. The former sample exhibits a clear tunneling anisotropic MR (TAMR), with the characteristic correlation between resistance and current direction, in contrast to the latter sample which displays a conventional tunneling MR (TMR) dominated by the relative orientation between the magnetization directions of the two electrodes. In addition, the TAMR has a much stronger temperature dependence than the TMR, indicating a much faster drop-off of the tunneling density of states anisotropy than the tunneling electron spin polarization with increasing temperature. Finally, we propose a possible simple way to distinguish TAMR from normal TMR by measuring the resistance of the device at different angles of the external magnetic field. 2008 American Institute of Physics.

Subject headings

NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Keyword

Tunnel junctions

Anisotropy

Coal

Coal industry

Electric resistance

Electrodes

Electronic structure

Magnetic field effects

Magnetic fields

Magnetoelectronics

Magnetoresistance

Semiconductor junctions

Spin dynamics

Tunneling (excavation)

Tunnels

Physics

Fysik

nickel

magnetisation

tunnelling magnetoresistance

magnetic thin films

gold

ferromagnetic materials

polarisation

electron spin

cobalt

aluminium compounds

band structure

Fysik

Publication and Content Type

ref (subject category)

art (subject category)