Electronic structures of new tunnel barrier spinel MgAl2O4:first-principles calculations
来源期刊：Rare Metals2012年第2期
论文作者：ZHANG Delin a , XU Xiaoguang a , WANG Wei b , ZHANG Xin a , YANG Hailing a , WU Yong a , MA Chuze a , and JIANG Yong a a State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing , China b Institute for Materials Research, Tohoku University, Sendai -, Japan
文章页码：112 - 116
摘 要：The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are found for the MgAl 2 O 4 and MgO tunneling barriers. The calculated direct energy gaps at the Γ-point are about 5.10 eV for MgAl 2 O 4 and 4.81 eV for MgO, respectively. Because of the similar feature in band structures from Γ high-symmetry point to F point （ band）, the coherent tunneling effect might be expected to appear in MgAl 2 O 4-based MTJs like in MgO-based MTJs. The small difference of the surface free energies of Fe （2.9 J m 2 ） and MgAl 2 O 4 （2.27 J m 2 ） on the {100} orientation, and the smaller lattice mismatch between MgAl 2 O 4 and ferromagnetic electrodes than that between MgO and ferromagnetic electrodes, the spinel MgAl 2 O 4 can substitute MgO to fabricate the coherent tunneling and chemically stable magnetic tunnel junction structures, which will be applied in the next generation read heads or spintronic devices.
ZHANG Delin a , XU Xiaoguang a , WANG Wei b , ZHANG Xin a , YANG Hailing a , WU Yong a , MA Chuze a , and JIANG Yong a a State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China b Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
摘 要：The electronic structures of spinel MgAl 2 O 4 and MgOtunnel barrier materials were investigated using first-principles density functional theory calculations. Our results show that similar electronic structures are found for the MgAl 2 O 4 and MgO tunneling barriers. The calculated direct energy gaps at the Γ-point are about 5.10 eV for MgAl 2 O 4 and 4.81 eV for MgO, respectively. Because of the similar feature in band structures from Γ high-symmetry point to F point （ band）, the coherent tunneling effect might be expected to appear in MgAl 2 O 4-based MTJs like in MgO-based MTJs. The small difference of the surface free energies of Fe （2.9 J m 2 ） and MgAl 2 O 4 （2.27 J m 2 ） on the {100} orientation, and the smaller lattice mismatch between MgAl 2 O 4 and ferromagnetic electrodes than that between MgO and ferromagnetic electrodes, the spinel MgAl 2 O 4 can substitute MgO to fabricate the coherent tunneling and chemically stable magnetic tunnel junction structures, which will be applied in the next generation read heads or spintronic devices.
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