Size Effect of Inserted Iron Nanoparticles in the MgO-Based Double Barrier Magnetic Tunnel Junction

作者：Lee Yen Chi; Lin Chia Hao; Mishra A K; Wu Te Ho; Wu Jong Ching^*

来源：IEEE Transactions on Magnetics, 2014, 50(1): 1401103.

DOI：10.1109/TMAG.2013.2276014

• Double barrier magnetic tunnel junction (DBMTJ)
• iron nanoparticles
• size effect

The transport properties of stacked CoFeB (1.86)/MgO (0.2)/Fe-nanoparticles (t(Fe))/MgO (0.5)/CoFeB(0.6) double barrier magnetic tunnel junctions have been characterized. In this investigation, stacked film is prepared by magnetron sputter system, annealed at 250 degrees, and patterned into a micron-scale device using standard electron beam lithography in conjunction with two-angle ion beam etching. First, the structure, magnetic and electrical properties are examined by using transmission electron microscopy, alternating gradient magnetometers, and lock-in techniques. Stacked film having 1.5 nm lateral size of iron nanoparticles (sample S1) exhibits an in-plane magnetic anisotropy, nonetheless the stacked film having 2 nm lateral size of iron nanoparticles (sample S5) possesses out-of-plane magnetic anisotropy. In addition, the micron scaled S1 device displays not only a normal in-plane magnetoresistance (MR) curve but also an anomalous out-of-plane MR behavior, whereas the S5 device only barely shows magnetic response in the in-plane MR. A hysteresis-free linear region in out-of-planeMRcurve has shown field sensitivity of similar to 36 Omega/Oe that is promising for magnetic field sensor applications.

• 出版日期2014-1