Fabrication of MgO-based magnetic tunnel junctions with CoCrPt perpendicularly magnetized electrodes

Journal of Applied Physics (Impact Factor: 2.21). 05/2009; DOI: 10.1063/1.3062816
Source: IEEE Xplore

ABSTRACT The applicability of perpendicularly magnetized CoCrPt films to the MgO-based magnetic tunnel junctions (MTJs) was investigated. For this study, CoCrPt films deposited on the Ru buffer exhibited hcp(0002)-oriented growth by sputtering method using the low substrate temperature of 250 ° C , low saturation magnetization of around 360 emu / cm 3 , and high magnetic anisotropy field of 6 kOe, which is sufficient to retain the thermal stability of the magnetization direction. The MgO-based MTJs with a synthetic ferrimagnetlike structure were fabricated: CoFe was coupled magnetically with CoCrPt through the thin Ru layer. Transport properties with a magnetic field applied perpendicular to the film plane revealed a tunnel magnetoresistance ratio of about 6% at room temperature.

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    ABSTRACT: Investigations of the structural and magnetic properties of thin Co50-xNixPt50 (x = 0, 10, 15, 37.5) films and fabrication of magnetic tunnel junctions (MTJs) using Co50Pt50 and Co35Ni15Pt50 electrodes were performed. X-ray diffraction analyses revealed that 20-nm-thick CoPt and CoNiPt films were epitaxially grown with (001)-orientation with an L10-chemical order parameter of 0.66–0.82. CoNiPt with various Ni contents magnetized perpendicularly; the saturation magnetization reduced to 157 emu/cm3 when the Ni content was increased to 37.5%. Magnetotransport measurements under a magnetic field applied perpendicular to the film plane revealed a tunnel magnetoresistance ratio of 10% and 1% at 10 K and 300 K, respectively, for MTJ using Co35Ni15Pt50 electrodes.
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