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▲ [18p-PB1-31] Tunnel magnetoresistance effect in the magnetic tunnel junctions with compensated ferrimagnetic Mn2(Co-V)Al Heusler alloy
Keywords:Heusler alloy, Ferrimagnet, TMR effect
In this study, we investigated the magnetic properties of the Mn2(Co-V)Al films and the tunnel magnetoresistance (TMR) effect for the magnetic tunnel junctions (MTJs) with its electrode to gain insight into its half-metallicity.
Samples were prepared by a magnetron sputtering technique. The stacking structures of the single layer samples and MTJs were MgO(001) sub./ Mn-Co-V-Al (30)/ MgO (2)/ Ru (2) and MgO(001) sub./ Mn-Co-V-Al (30)/ Mg (0.4)/ MgO (2)/ CoFe (5)/ IrMn (10)/ Ru (8) (thickness is in nm), respectively. The composition of Mn-Co-V-Al layer was changed by co-sputtering technique. The Mn-Co-V-Al layer was deposited at 700ºC and the other layers were deposited at the room temperature (RT). The crystalline structures were characterized by x-ray diffraction (XRD). The magnetic properties were measured by a vibrating sample magnetometer (VSM). The microfabrication of the MTJs were performed using a standard photo-lithography technique. The TMR effect was measured by a four-probe method.
Mn2VAl and Mn2Co0.5V0.5Al samples showed (111) super lattice diffraction peak, which indicating the L21 or XA ordering. The saturation magnetization for Mn-Co-V-Al films for each composition were smaller than the bulk values. However, its composition dependence was similar to that for bulk experiments, and the magnetization compensation was confirmed for Mn2Co0.5V0.5Al. The TMR effects were observed for Mn-Co-V-Al films and the TMR ratios were -0.5%, 0.12% and 0.05% at room temperature for Mn2VAl, Mn2CoAl and Mn2Co0.5V0.5Al, respectively. These signs of TMR effects for Mn-Co-V-Al were consistent with the spin polarization for those alloys predicted from the first principles calculation.
Samples were prepared by a magnetron sputtering technique. The stacking structures of the single layer samples and MTJs were MgO(001) sub./ Mn-Co-V-Al (30)/ MgO (2)/ Ru (2) and MgO(001) sub./ Mn-Co-V-Al (30)/ Mg (0.4)/ MgO (2)/ CoFe (5)/ IrMn (10)/ Ru (8) (thickness is in nm), respectively. The composition of Mn-Co-V-Al layer was changed by co-sputtering technique. The Mn-Co-V-Al layer was deposited at 700ºC and the other layers were deposited at the room temperature (RT). The crystalline structures were characterized by x-ray diffraction (XRD). The magnetic properties were measured by a vibrating sample magnetometer (VSM). The microfabrication of the MTJs were performed using a standard photo-lithography technique. The TMR effect was measured by a four-probe method.
Mn2VAl and Mn2Co0.5V0.5Al samples showed (111) super lattice diffraction peak, which indicating the L21 or XA ordering. The saturation magnetization for Mn-Co-V-Al films for each composition were smaller than the bulk values. However, its composition dependence was similar to that for bulk experiments, and the magnetization compensation was confirmed for Mn2Co0.5V0.5Al. The TMR effects were observed for Mn-Co-V-Al films and the TMR ratios were -0.5%, 0.12% and 0.05% at room temperature for Mn2VAl, Mn2CoAl and Mn2Co0.5V0.5Al, respectively. These signs of TMR effects for Mn-Co-V-Al were consistent with the spin polarization for those alloys predicted from the first principles calculation.