J. Semicond. > 2017, Volume 38 > Issue 6 > 062003
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SEMICONDUCTOR PHYSICS

Study on the mechanism of perpendicular magnetic anisotropy in Ta/CoFeB/MgO system

Yongle Lou1, Yuming Zhang1, Hui Guo1, , Daqing Xu2 and Yimen Zhang1

+ Author Affiliations

 Corresponding author: Hui Guo Email:guohui@mail.xidian.edu.cn

DOI: 10.1088/1674-4926/38/6/062003

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Abstract: The mechanism of perpendicular magnetic anisotropy (PMA) in a MgO-based magnetic tunnel junction (MTJ) has been studied in this article. By comparing the magnetic properties and elementary composition analysis for different CoFeB-based structures, such as Ta/CoFeB/MgO, Ta/CoFeB/Ta and Ru/CoFeB/MgO structures, it is found that a certain amount of Fe-oxide existing at the interface of CoFeB/MgO is helpful to enhance the PMA and the PMA is originated from the interface of CoFeB/MgO. In addition, Ta film plays an important role to enhance the PMA in Ta/CoFeB/MgO structure.

Key words: perpendicular magnetic anisotropy, MgO-based MTJ, X-ray photoelectron spectroscopy, Fe-oxide



[1]
Kent A D, Worledge D C. A new spin on magnetic memories. Nat Nanotechnol, 2015, 10(3):187 doi: 10.1038/nnano.2015.24
[2]
Matsukura F, Tokura Y, Ohno H. Control of magnetism by electric fields. Nat Nanotechnol, 2015, 10(3):209 doi: 10.1038/nnano.2015.22
[3]
Yu G Q, Upadhyaya P, Fan Y B, et al. Switching of perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields. Nat Nanotechnol, 2014, 9(7):548 doi: 10.1038/nnano.2014.94
[4]
Brataas A, Kent A D, Ohno H. Current-induced torques in magnetic materials. Nat Mater, 2012, 11(5):372 doi: 10.1038/nmat3311
[5]
Wang W G, Li M, Hageman S, et al. Electric-field-assisted switching in magnetic tunnel junctions. Nat Mater, 2012, 11(1):64 http://www.nature.com/nmat/journal/v11/n1/fig_tab/nmat3171_F2.html
[6]
Qiu X P, Deorani P, Narayanapillai K, et al. Angular and temperature dependence of current induced spin-orbit effective fields in Ta/CoFeB/MgO nanowires. Sci Rep, 2014, 4(3):528 https://koreauniv.pure.elsevier.com/en/publications/angular-and-temperature-dependence-of-current-induced-spin-orbit-
[7]
Wang Z, Zhao W, Deng E, et al. Perpendicular-anisotropy magnetic tunnel junction switched by spin-Hall-assisted spin-transfer torque. J Phys D Appl Phys, 2015, 48(6):065001 doi: 10.1088/0022-3727/48/6/065001
[8]
Peng S Z, Wang M X, Yang H X, et al. Origin of interfacial perpendicular magnetic anisotropy in MgO/CoFe/metallic capping layer structures. Sci Rep, 2015, 5:18173 https://arxiv.org/pdf/1506.04078
[9]
Gottwald M, Kan J J, Lee K, et al. Scalable and thermally robust perpendicular magnetic tunnel junctions for STT-MRAM. Appl Phys Lett, 2015, 106(3):952 http://adsabs.harvard.edu/abs/2015ApPhL.106c2413G
[10]
Harnsoongnoen S, Surawanitkun C. Fast switching in thermoelectric spin-transfer torque MRAM with temperature increase caused by Peltier effect. Integr Ferroelectr, 2015, 165(1):98 doi: 10.1080/10584587.2015.1062703
[11]
Nishimura N, Hirai T, Koganei A, et al. Magnetic tunnel junction device with perpendicular magnetization films for high-density magnetic random access memory. J Appl Phys, 2002, 91(8):5246 doi: 10.1063/1.1459605
[12]
Ohmori H, Hatori T, Nakagawa S. Perpendicular magnetic tunnel junction with tunneling magnetoresistance ratio of 64% using MgO (100) barrier layer prepared at room temperature. J Appl Phys, 2008, 103(7):07A911 doi: 10.1063/1.2840016
[13]
Nakayama M, Kai T, Shimomura N, et al. Spin transfer switching in TbCoFe/CoFeB/MgO/CoFeB/TbCoFe magnetic tunnel junctions with perpendicular magnetic anisotropy. J Appl Phys, 2008, 103(7):07A710 https://www.researchgate.net/publication/234958693_Spin_transfer_switching_in_TbCoFeCoFeBMgOCoFeBTbCoFe_magnetic_tunnel_junctions_with_perpendicular_magnetic_anisotropy
[14]
Chiaramonti A N, Schreiber D K, Egelhoff W F, et al. Effects of annealing on local composition and electrical transport correlations in MgO-based magnetic tunnel junctions. Appl Phys Lett, 2008, 93(10):511 https://www.researchgate.net/profile/Ann_Chiaramonti/publication/234876750_Effects_of_annealing_on_local_composition_and_electrical_transport_correlations_in_MgO-based_magnetic_tunnel_junctions/links/55c8c77a08aea2d9bdc91c54.pdf?inViewer=true&disableCoverPage=true&origin=publication_detail
[15]
Rahman M T, Lyle A, Hu G, et al. High temperature annealing stability of magnetic properties in MgO-based perpendicular magnetic tunnel junction stacks with CoFeB polarizing layer. J Appl Phys, 2011, 109(7):07C709 https://www.researchgate.net/publication/234931894_High_temperature_annealing_stability_of_magnetic_properties_in_MgO-based_perpendicular_magnetic_tunnel_junction_stacks_with_CoFeB_polarizing_layer
[16]
Cheng T, Cheng C, Chern G. Perpendicular magnetic anisotropy induced by a cap layer in ultrathin MgO/CoFeB/Nb. J Appl Phys, 2012, 112(112):33910 https://www.researchgate.net/publication/257973015_Perpendicular_magnetic_anisotropy_induced_by_a_cap_layer_in_ultrathin_MgOCoFeBNb
[17]
Li X J, Jiang S L, Zhang J Y, et al. Enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers by inhibiting Ta diffusion. Appl Surf Sci, 2016, 365:275 doi: 10.1016/j.apsusc.2016.01.032
[18]
Ikeda S, Miura K, Yamamoto H, et al. A perpendicular-anisotropy CoFeB/MgO magnetic tunnel junction. Nat Mater, 2010, 9(9):721 doi: 10.1038/nmat2804
[19]
Jung J H, Lim S H, Lee S R. Strong perpendicular magnetic anisotropy in thick CoFeB films sandwiched by Pd and MgO layers. Appl Phys Lett, 2010, 96(4):042503 doi: 10.1063/1.3299009
[20]
Wang W X, Yang Y, Naganuma H, et al. The perpendicular anisotropy of Co40Fe40B20 sandwiched between Ta and MgO layers and its application in CoFeB/MgO/CoFeB tunnel junction. Appl Phys Lett, 2011, 99(1):012502 doi: 10.1063/1.3605564
[21]
Fowley C, Decorde N, Oguz K, et al. Perpendicular magnetic anisotropy in CoFeB/Pd bilayers.IEEE Trans Magn, 2010, 46(6):2116 doi: 10.1109/TMAG.2010.2044374
[22]
Cheng C W, Feng W, Chern G, et al. Effect of cap layer thickness on the perpendicular magnetic anisotropy in top MgO/CoFeB/Ta structures. J Appl Phys, 2011, 110(110):033916 https://www.researchgate.net/publication/234962735_Effect_of_cap_layer_thickness_on_the_perpendicular_magnetic_anisotropy_in_top_MgOCoFeBTa_structures
[23]
Ma Q L, Iihama S, Kubota T, et al. Effect of Mg interlayer on perpendicular magnetic anisotropy of CoFeB films in MgO/Mg/CoFeB/Ta structure. Appl Phys Lett, 2012, 101(12):122414 doi: 10.1063/1.4754118
[24]
Shimabukuro R, Nakamura K, Akiyama T, et al. Electric field effects on magnetocrystalline anisotropy in ferromagnetic Fe monolayers. Physica E, 2010, 42(4):1014 doi: 10.1016/j.physe.2009.11.110
[25]
Read J C, Mather P G, Buhrman R A. X-ray photoemission study of CoFeB/MgO thin film bilayers. Appl Phys Lett, 2007, 90(13):132503 doi: 10.1063/1.2717091
[26]
Wang W G, Hageman S, Li M, et al. Rapid thermal annealing study of magnetoresistance and perpendicular anisotropy in mag-netic tunnel junctions based on MgO and CoFeB.Appl Phys Lett, 2011, 99(10):102502 doi: 10.1063/1.3634026
[27]
Worledge D C, Hu G, Abraham D W, et al. Spin torque switching of perpendicular Ta/CoFeB/MgO-based magnetic tunnel junctions. Appl Phys Lett, 2011, 98(2):022501 doi: 10.1063/1.3536482
[28]
Liu T, Cai J W, Sun L. Large enhanced perpendicular magnetic anisotropy in CoFeB/MgO system with the typical Ta buffer replaced by an Hf layer. AIP Adv, 2012, 2(3):413 http://www.oalib.com/paper/2423942
[29]
Zhu Y, Han N. Research on enhanced perpendicular magnetic anisotropy in CoFe/Pd bilayer structure. Acta Phys Sin, 2012, 61(16):167505 http://wulixb.iphy.ac.cn/EN/Y2012/V61/I16/0167505
[30]
Neudert A, McCord J. Dynamic anisotropy in amorphous CoZrTa films. J Appl Phys, 2004, 95(11):6595 doi: 10.1063/1.1667796
[31]
Ibusuki T, Miyajima T, Umehara S, et al. Lower-temperature crystallization of CoFeB in MgO magnetic tunnel junctions by using Ti capping layer. Appl Phys Lett, 2009, 94(6):062509 doi: 10.1063/1.3080208
Fig. 1.  (Color online) In-plane and out-of-plane magnetic hysteresis loops of sample S1.

DownLoad: Full-Size Img PowerPoint
Fig. 2.  (Color online) In-plane and out-of-plane magnetic hysteresis loops of sample S2.

DownLoad: Full-Size Img PowerPoint
Fig. 3.  (Color online) XPS depth profile for sample S1.

DownLoad: Full-Size Img PowerPoint
Fig. 4.  TEM image for (a) CoFeB/MgO layers and (b) Ta/CoFeB/Ta layers after annealing.

DownLoad: Full-Size Img PowerPoint
Fig. 5.  (Color online) In-plane and out-of-plane magnetic hysteresis loops of sample S3.

DownLoad: Full-Size Img PowerPoint
[1]
Kent A D, Worledge D C. A new spin on magnetic memories. Nat Nanotechnol, 2015, 10(3):187 doi: 10.1038/nnano.2015.24
[2]
Matsukura F, Tokura Y, Ohno H. Control of magnetism by electric fields. Nat Nanotechnol, 2015, 10(3):209 doi: 10.1038/nnano.2015.22
[3]
Yu G Q, Upadhyaya P, Fan Y B, et al. Switching of perpendicular magnetization by spin-orbit torques in the absence of external magnetic fields. Nat Nanotechnol, 2014, 9(7):548 doi: 10.1038/nnano.2014.94
[4]
Brataas A, Kent A D, Ohno H. Current-induced torques in magnetic materials. Nat Mater, 2012, 11(5):372 doi: 10.1038/nmat3311
[5]
Wang W G, Li M, Hageman S, et al. Electric-field-assisted switching in magnetic tunnel junctions. Nat Mater, 2012, 11(1):64 http://www.nature.com/nmat/journal/v11/n1/fig_tab/nmat3171_F2.html
[6]
Qiu X P, Deorani P, Narayanapillai K, et al. Angular and temperature dependence of current induced spin-orbit effective fields in Ta/CoFeB/MgO nanowires. Sci Rep, 2014, 4(3):528 https://koreauniv.pure.elsevier.com/en/publications/angular-and-temperature-dependence-of-current-induced-spin-orbit-
[7]
Wang Z, Zhao W, Deng E, et al. Perpendicular-anisotropy magnetic tunnel junction switched by spin-Hall-assisted spin-transfer torque. J Phys D Appl Phys, 2015, 48(6):065001 doi: 10.1088/0022-3727/48/6/065001
[8]
Peng S Z, Wang M X, Yang H X, et al. Origin of interfacial perpendicular magnetic anisotropy in MgO/CoFe/metallic capping layer structures. Sci Rep, 2015, 5:18173 https://arxiv.org/pdf/1506.04078
[9]
Gottwald M, Kan J J, Lee K, et al. Scalable and thermally robust perpendicular magnetic tunnel junctions for STT-MRAM. Appl Phys Lett, 2015, 106(3):952 http://adsabs.harvard.edu/abs/2015ApPhL.106c2413G
[10]
Harnsoongnoen S, Surawanitkun C. Fast switching in thermoelectric spin-transfer torque MRAM with temperature increase caused by Peltier effect. Integr Ferroelectr, 2015, 165(1):98 doi: 10.1080/10584587.2015.1062703
[11]
Nishimura N, Hirai T, Koganei A, et al. Magnetic tunnel junction device with perpendicular magnetization films for high-density magnetic random access memory. J Appl Phys, 2002, 91(8):5246 doi: 10.1063/1.1459605
[12]
Ohmori H, Hatori T, Nakagawa S. Perpendicular magnetic tunnel junction with tunneling magnetoresistance ratio of 64% using MgO (100) barrier layer prepared at room temperature. J Appl Phys, 2008, 103(7):07A911 doi: 10.1063/1.2840016
[13]
Nakayama M, Kai T, Shimomura N, et al. Spin transfer switching in TbCoFe/CoFeB/MgO/CoFeB/TbCoFe magnetic tunnel junctions with perpendicular magnetic anisotropy. J Appl Phys, 2008, 103(7):07A710 https://www.researchgate.net/publication/234958693_Spin_transfer_switching_in_TbCoFeCoFeBMgOCoFeBTbCoFe_magnetic_tunnel_junctions_with_perpendicular_magnetic_anisotropy
[14]
Chiaramonti A N, Schreiber D K, Egelhoff W F, et al. Effects of annealing on local composition and electrical transport correlations in MgO-based magnetic tunnel junctions. Appl Phys Lett, 2008, 93(10):511 https://www.researchgate.net/profile/Ann_Chiaramonti/publication/234876750_Effects_of_annealing_on_local_composition_and_electrical_transport_correlations_in_MgO-based_magnetic_tunnel_junctions/links/55c8c77a08aea2d9bdc91c54.pdf?inViewer=true&disableCoverPage=true&origin=publication_detail
[15]
Rahman M T, Lyle A, Hu G, et al. High temperature annealing stability of magnetic properties in MgO-based perpendicular magnetic tunnel junction stacks with CoFeB polarizing layer. J Appl Phys, 2011, 109(7):07C709 https://www.researchgate.net/publication/234931894_High_temperature_annealing_stability_of_magnetic_properties_in_MgO-based_perpendicular_magnetic_tunnel_junction_stacks_with_CoFeB_polarizing_layer
[16]
Cheng T, Cheng C, Chern G. Perpendicular magnetic anisotropy induced by a cap layer in ultrathin MgO/CoFeB/Nb. J Appl Phys, 2012, 112(112):33910 https://www.researchgate.net/publication/257973015_Perpendicular_magnetic_anisotropy_induced_by_a_cap_layer_in_ultrathin_MgOCoFeBNb
[17]
Li X J, Jiang S L, Zhang J Y, et al. Enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers by inhibiting Ta diffusion. Appl Surf Sci, 2016, 365:275 doi: 10.1016/j.apsusc.2016.01.032
[18]
Ikeda S, Miura K, Yamamoto H, et al. A perpendicular-anisotropy CoFeB/MgO magnetic tunnel junction. Nat Mater, 2010, 9(9):721 doi: 10.1038/nmat2804
[19]
Jung J H, Lim S H, Lee S R. Strong perpendicular magnetic anisotropy in thick CoFeB films sandwiched by Pd and MgO layers. Appl Phys Lett, 2010, 96(4):042503 doi: 10.1063/1.3299009
[20]
Wang W X, Yang Y, Naganuma H, et al. The perpendicular anisotropy of Co40Fe40B20 sandwiched between Ta and MgO layers and its application in CoFeB/MgO/CoFeB tunnel junction. Appl Phys Lett, 2011, 99(1):012502 doi: 10.1063/1.3605564
[21]
Fowley C, Decorde N, Oguz K, et al. Perpendicular magnetic anisotropy in CoFeB/Pd bilayers.IEEE Trans Magn, 2010, 46(6):2116 doi: 10.1109/TMAG.2010.2044374
[22]
Cheng C W, Feng W, Chern G, et al. Effect of cap layer thickness on the perpendicular magnetic anisotropy in top MgO/CoFeB/Ta structures. J Appl Phys, 2011, 110(110):033916 https://www.researchgate.net/publication/234962735_Effect_of_cap_layer_thickness_on_the_perpendicular_magnetic_anisotropy_in_top_MgOCoFeBTa_structures
[23]
Ma Q L, Iihama S, Kubota T, et al. Effect of Mg interlayer on perpendicular magnetic anisotropy of CoFeB films in MgO/Mg/CoFeB/Ta structure. Appl Phys Lett, 2012, 101(12):122414 doi: 10.1063/1.4754118
[24]
Shimabukuro R, Nakamura K, Akiyama T, et al. Electric field effects on magnetocrystalline anisotropy in ferromagnetic Fe monolayers. Physica E, 2010, 42(4):1014 doi: 10.1016/j.physe.2009.11.110
[25]
Read J C, Mather P G, Buhrman R A. X-ray photoemission study of CoFeB/MgO thin film bilayers. Appl Phys Lett, 2007, 90(13):132503 doi: 10.1063/1.2717091
[26]
Wang W G, Hageman S, Li M, et al. Rapid thermal annealing study of magnetoresistance and perpendicular anisotropy in mag-netic tunnel junctions based on MgO and CoFeB.Appl Phys Lett, 2011, 99(10):102502 doi: 10.1063/1.3634026
[27]
Worledge D C, Hu G, Abraham D W, et al. Spin torque switching of perpendicular Ta/CoFeB/MgO-based magnetic tunnel junctions. Appl Phys Lett, 2011, 98(2):022501 doi: 10.1063/1.3536482
[28]
Liu T, Cai J W, Sun L. Large enhanced perpendicular magnetic anisotropy in CoFeB/MgO system with the typical Ta buffer replaced by an Hf layer. AIP Adv, 2012, 2(3):413 http://www.oalib.com/paper/2423942
[29]
Zhu Y, Han N. Research on enhanced perpendicular magnetic anisotropy in CoFe/Pd bilayer structure. Acta Phys Sin, 2012, 61(16):167505 http://wulixb.iphy.ac.cn/EN/Y2012/V61/I16/0167505
[30]
Neudert A, McCord J. Dynamic anisotropy in amorphous CoZrTa films. J Appl Phys, 2004, 95(11):6595 doi: 10.1063/1.1667796
[31]
Ibusuki T, Miyajima T, Umehara S, et al. Lower-temperature crystallization of CoFeB in MgO magnetic tunnel junctions by using Ti capping layer. Appl Phys Lett, 2009, 94(6):062509 doi: 10.1063/1.3080208

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    Received: 20 September 2016 Revised: 21 December 2016 Online: Published: 01 June 2017

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      Article Navigation >  Journal of Semiconductors  > 2017  >  38(6): 062003
      Yongle Lou, Yuming Zhang, Hui Guo, Daqing Xu, Yimen Zhang. Study on the mechanism of perpendicular magnetic anisotropy in Ta/CoFeB/MgO system[J]. Journal of Semiconductors, 2017, 38(6): 062003. doi: 10.1088/1674-4926/38/6/062003 ****Y L Lou, Y M Zhang, H Guo, D Q Xu, Y M Zhang. Study on the mechanism of perpendicular magnetic anisotropy in Ta/CoFeB/MgO system[J]. J. Semicond., 2017, 38(6): 062003. doi: 10.1088/1674-4926/38/6/062003.
      Citation:
      Yongle Lou, Yuming Zhang, Hui Guo, Daqing Xu, Yimen Zhang. Study on the mechanism of perpendicular magnetic anisotropy in Ta/CoFeB/MgO system[J]. Journal of Semiconductors, 2017, 38(6): 062003. doi: 10.1088/1674-4926/38/6/062003 ****
      Y L Lou, Y M Zhang, H Guo, D Q Xu, Y M Zhang. Study on the mechanism of perpendicular magnetic anisotropy in Ta/CoFeB/MgO system[J]. J. Semicond., 2017, 38(6): 062003. doi: 10.1088/1674-4926/38/6/062003.
      shu

      Study on the mechanism of perpendicular magnetic anisotropy in Ta/CoFeB/MgO system

      DOI: 10.1088/1674-4926/38/6/062003
      • 1.

        School of Microelectronics, Xidian University, Key laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xi'an 710071, China

      • 2.

        School of Electrical and Control Engineering, Xi'an University of Science and Technology, Xi'an 710054, China

      Funds:

      the Scientific Research Program Funded by Shaanxi Provincial Education Department 11JK0912

      Project supported by the National Defense Advance Research Foundation (No. 9140A08XXXXXX0DZ106), the Basic Research Program of Ministry of Education, China (No. JY10000925005), the Scientific Research Program Funded by Shaanxi Provincial Education Department (No.11JK0912), the Scientific Research Foundation of Xi'an University of Science and Technology (No. 2010011), the Doctoral Research Startup Fund of Xi'an University of Science and Technology (No. 2010QDJ029)

      the National Defense Advance Research Foundation 9140A08XXXXXX0DZ106

      the Basic Research Program of Ministry of Education, China JY10000925005

      the Scientific Research Foundation of Xi'an University of Science and Technology 2010011

      the Doctoral Research Startup Fund of Xi'an University of Science and Technology 2010QDJ029

      More Information
      • Corresponding author: Hui Guo Email:guohui@mail.xidian.edu.cn
      • Received Date: 2016-09-20
      • Revised Date: 2016-12-21
      • Published Date: 2017-06-01

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