[10p-Z08-11~17] 10.3 スピンデバイス・磁気メモリ・ストレージ技術

▲ [10p-Z08-11] [The 42nd JSAP Paper Award Speech] CoFeB/MgO-based magnetic tunnel junction directly formed on a flexible substrate

Shinya Ota^1,2、Masaki Ono¹、Hiroki Matsumoto^1,2、Akira Ando²、Tsuyoshi Sekitani²、Ryuhei Kohno¹、Shogo Iguchi¹、Tomohiro Koyama^2,1,3、〇Daichi Chiba^2,1,3 (1.The Univ. of Tokyo、2.ISIR, Osaka Univ.、3.CSRN, Osaka Univ.)

キーワード：spintronics, flexible spintronics, magnetic tunnel junction

Here we succeeded in fabricating a CoFeB/MgO-based magnetic tunnel junction (MTJ) directly on an organic flexible substrate. As the annealing temperature increases, the tunnel magnetoresistance (TMR) ratio enhances and reaches up to ~200% at an annealing temperature of 450^oC. The TMR ratio shows no change during and after a 1000-cycle application of a tensile strain larger than 1%. The magnetic anisotropy fields for the top and bottom CoFeB layers are linearly proportional to strain with almost the same rate as that in a single CoFeB film, suggesting that the expected strain is added on both CoFeB layers in the MTJ pillar from the stretched flexible substrate. The high TMR ratio and strain endurance demonstrated in this study show that the flexible MTJ structure is a promising candidate for a future wearable sensing device.