Title :
Tunneling current-induced butterfly-shaped domains and magnetization switching in double-barrier magnetic tunnel junctions
Author :
Zhao, S.F. ; Zhao, J. ; Zeng, Z.M. ; Han, X.F. ; Ando, Y. ; Miyazaki, T.
Author_Institution :
State Key Lab. of Magnetism, Chinese Acad. of Sci., Beijing, China
Abstract :
Double barrier magnetic tunnel junction (DBMTJ) with layer structures Ta/Cu/Ni79Fe21/Ir22Mn78/Co75Fe25/Al -oxide/Ni79Fe21/Al-oxide/Co75Fe25/Ir22Mn78/ Py/Cu/Ta are deposited on Si/SiO2 wafer using magnetron sputtering. Tunneling magnetoresistance(TMR) ratio of 18.7% and 28.4%, resistance-area product RS of around 12.7 and 10.3 kΩμm2 and coercivity of 17.5 and 2.0 Oe at room temperature are obtained for the DBMTJ. Micromagnetic simulations for the dynamic domain structures under increasing DC current and the magnetic switching properties are done using the energy minimization method. The magnetocrystalline anisotropy constant K1=1.0×103 erg/cm3, spontaneous magnetization Ms=800 Oe, and exchange interaction constant A=1.0×10-6 erg/cm values for the free layer are taken from the parameters of Ni79Fe21 alloy. The simulations show that the dynamic butterfly-shaped domains and magnetization switching can occur in the free layer when a DC current passes through the DBMTJ on the order of 100 μA to 10 mA, under a DC bias voltage of 10-1000 mV. It decreases the magnetization in the free layer which results into the low TMR ratio observed in the DBMTJ.
Keywords :
aluminium compounds; antiferromagnetic materials; cobalt alloys; coercive force; copper; exchange interactions (electron); ferromagnetic materials; iridium alloys; iron alloys; magnetic anisotropy; magnetic domains; magnetic multilayers; magnetic switching; manganese alloys; micromagnetics; nickel alloys; sputter deposition; tantalum; tunnelling magnetoresistance; 10 to 1000 mV; 293 to 298 K; DC bias voltage; DC current; Si-SiO2; TMR; Ta-Cu-Ni79Fe21-Ir22Mn78-Co75Fe25-Al; coercivity; double barrier magnetic tunnel junction; dynamic butterfly-shaped domains; energy minimization method; exchange interaction constant; free layer; magnetic switching; magnetocrystalline anisotropy constant; magnetron sputtering; micromagnetic simulations; resistance-area product; room temperature; spontaneous magnetization; tunneling magnetoresistance ratio; Coercive force; Iron; Magnetic anisotropy; Magnetic domains; Magnetic switching; Magnetic tunneling; Magnetization; Perpendicular magnetic anisotropy; Sputtering; Tunneling magnetoresistance;
Conference_Titel :
Magnetics Conference, 2005. INTERMAG Asia 2005. Digests of the IEEE International
Print_ISBN :
0-7803-9009-1
DOI :
10.1109/INTMAG.2005.1463938