Superparamagnetism in MgO-based magnetic tunnel junctions with a thin pinned ferromagnetic electrode

Ferromagnetic resonance and damping properties of CoFeB thin films as free layers in MgO-based magnetic tunnel junctions

MgO-based double barrier magnetic tunnel junctions with thin free layers

The free layer thickness tfree in double barrier magnetic tunnel junctions DMTJs based on crystalline MgO barriers and CoFeB ferromagnetic layers has been varied from 0.5 to 3.0 nm in order to investigate its effect on the magnetic and electrical properties. One obvious feature of DMTJs with tfree 1 nm is the absence of sharp free layer switching in the TMR curves, which can be explained by the...

Annealing of CoFeB/MgO based single and double barrier magnetic tunnel junctions: Tunnel magnetoresistance, bias dependence, and output voltage

Co40Fe40B20 /MgO single and double barrier magnetic tunnel junctions MTJs were grown using target-facing-target sputtering for MgO barriers and conventional dc magnetron sputtering for Co40Fe40B20 ferromagnetic electrodes. Large tunnel magnetoresistance TMR ratios, 230% for single barrier MTJs and 120% for the double barrier MTJs, were obtained after postdeposition annealing in a field of 800 m...

Effect of defects in Heusler alloy thin films on spin-dependent tunnelling characteristics of Co2MnSi/MgO/Co2MnSi and Co2MnGe/MgO/Co2MnGe magnetic tunnel junctions.

Fully epitaxial magnetic tunnel junctions (MTJs) with Co-based Heusler alloy Co(2)MnSi electrodes and a MgO tunnel barrier were fabricated with various values of Mn composition α for Co(2)Mn(α)Si in Co(2)Mn(α)Si/MgO/Co(2)Mn(α)Si MTJs. The tunnel magnetoresistance (TMR) ratios at both 4.2 K and room temperature (RT) increased systematically with increasing α in Co(2)Mn(α)Si electrodes from Mn-de...

Annealing effect on tunneling magnetoresistance in MgO-based magnetic tunnel junctions with FeMn exchange-bias layer

MgO-based magnetic tunnel junctions were fabricated, with a thin pinned CoFeB layer in the unbalanced synthetic antiferromagnet part of the stack FeMn/CoFe/Ru/CoFeB. Inverted and normal tunneling magnetoresistance (TMR) values occur at low and high annealing temperatures (Ta), respectively. The TMR ratio remains inverted up to Ta = 300 °C and it becomes normal around Ta = 350 °C. The exchange b...