Electrical manipulation of magnetization switching in Co2FeAl alloy based magnetic tunnel junctions with in-plane and perpendicular magnetization
Electrical manipulation of magnetization switching, such as spin-transfer torque (STT) switching, electric-field-assistant magnetization switching, and spin-orbit torque (SOT) switching, has been attracting great attentions due to its applications in low-power-consumption spintronic devices, such as magnetoresistive random access memories (MRAMs) and non-volatile magnetic-logic circuits. Recent investigations of electrical manipulation of magnetization switching in magnetic tunnel junctions (MTJs) have mainly been carried out in CoFeB/MgO/CoFeB structures. However, the switching current density of those MTJs is still too high for the scaling of gigabit MRAMs. Therefore, the establishment of new ferromagnetic materials for MTJs is greatly desired.
Spin-transfer switching in full-Heusler Co2FeAl-based magnetic tunnel junctions
We demonstrated spin-transfer magnetization switching using magnetic tunnel junctions (MTJs) with a full-Heusler alloy Co2FeAl (CFA). We prepared CFA (1.5 nm)/MgO/CoFe (4 nm) (“CFA-free”) and CFA (30 nm)/MgO/CoFeB (2 nm) (“CFA-reference”) MTJs on a Cr(001) layer. The intrinsic critical current density (Jc0) of the CFA-free (CFA-reference) MTJ was 29 MA/cm2 (7.1 MA/cm2). The larger Jc0 of the CFA-free MTJ is attributed to the significant enhancement of the Gilbert damping factor (∼0.04) of the CFA due to the Cr layer. The Jc0 of the CFA-reference is as small as that reported for typical CoFeB/MgO/CoFeB MTJs.
5.63 and 5.80 MeV levels of Ne20; de-excitation branching
Abstract The ratio Г γ /Г for the 5.63 and 5.80 MeV levels of Ne 20 has been determined to be 0.077 (±0.008) and −4 , respectively, by using the C 12 (C 12 , α)Ne 20 reaction and determining the fraction of the events in which the alpha-particle and the Ne 20 recoil are present in coincidence at the kinematically correct angles. In both cases these results in themselves are shown to imply radiative E1 transition (5.63→1.63 and 5.80→0, respectively) probabilities ⪡5 × 10 −5 Weisskopf units. When taken together with the life-time for the 5.63 MeV level measured by Evans et al . values of Г( E1 ) ≲ 5 × 10 −6 and Г α ≈ 6% of the particle estimate are obtained for this state.