Title

鎳鐵/鎳鐵氧化物雙層薄膜顯微結構之分析及其交換偏壓性質之探討

Translated Titles

Microstructural analysis of NiFe/NixFe1-xO thin-film bilayer and associated properties of exchange bias

Authors

劉家政

Key Words

交換偏壓 ; 交換偶合 ; Ni80Fe20/NixFe1-xO ; multislice

PublicationName

中興大學材料科學與工程學系所學位論文

Volume or Term/Year and Month of Publication

2006年

Academic Degree Category

碩士

Advisor

歐陽浩

Content Language

繁體中文

Chinese Abstract

由於鐵磁和反鐵磁薄膜間的界面交換偶合行為過去常被廣泛用於去固定磁性自旋閥或穿遂接合中某一層的磁化作用。本研究為了更進一步去探究界面間結構在交換偶合上的影響,因此,一系列Ni80Fe20/NixFe1-xO雙層薄膜利用雙離子束沉積技術隨著不同沉積條件(VEH=80V、100V、120V and 150V)而被製備,而這些不同條件的Ni80Fe20/NixFe1-xO雙層薄膜則引起不同混合的鐵磁和反鐵磁相,藉此去研究轟擊損壞在磁區壁楔鎖作用上的可能影響。另外,從multislice模擬的橫截面的高解析電子顯微鏡(cross-sectional HRTEM)研究結果顯示: Ni80Fe20是由f.c.c. Ni3Fe (a = 3.545Å)所組成,另外NixFe1-xO固溶體則是由f.c.c. NiO (a = 4.177Å)、R-3c α-Fe2O3 (a = 5.035Å , c = 13.74 Å) 和 f.c.c. FeO (a = 4.307Å)所構成。若依照HRTEM和EELS的結果也顯示出,對於VEH=80V、120V 和 150V條件下界面佔優勢的影響主要是反鐵磁,隨著一種常見的負交換偏壓在這些系統中被觀察到 ; 反之,在VEH=100V條件下會有一種鐵磁特性存在於界面而使其存在局部的有效場,因此提供零場冷下就觀察到正交換偏壓的可能條件。然而,在VEH=100V、120V and 150V條件下的Ni80Fe20/NixFe1-xO雙層薄膜的鐵磁層中,一種垂直於薄膜表面的柱狀結構被觀察到,且鐵磁層和反鐵磁層的厚度分別約為20 nm和30 nm。 隨著VEH的改變,Hc和VEH間有很強地線性關係,表現出更高能量的O2離子轟擊會去改變磁區壁楔鎖作用的性質,且導致不同地NixFe1-xO固溶體磁性相的組成。此外,在Ni80Fe20/NixFe1-xO雙層薄膜中也觀察到交換偏壓場(Hex)的很強溫度關係,強度隨著溫度遞減而增加。且當薄膜於零場冷下即可觀察到一種正的Hex(T),帶有一種(1-T/Tcrit)一致性的關係,而此種線性關係正好相符於所量測交換偏壓起始溫度的fitted Tcrit=220±10。而此種交換偏壓(Hex)的(1-T/Tcrit)溫度發展象徵一種反鐵磁力矩偶合於鐵磁層所產生domain-like區域方面上界面間自旋偏壓的不平衡,而其產生出的domain-like區域對於所量測到的迴路位移則是很重要的。 在這個研究裡,於零場冷條件下於T=10 K時有一種獨特的正交換偏壓位移(90Oe)現象被觀察到,因此針對不同場冷條件下所具有奇特的雙重正、負交換偏壓現象,我們將其物理起源歸因於一種複雜的界面間Ni80Fe20/NixFe1-xO結構,而這些主要是由不同沉積條件下(VEH=80V、100V、120V and 150V)高能離子束轟擊影響所造成。因此,本研究詳細地完成薄膜界面間結構組成分析,且能夠去確定NixFe1-xO固溶體是一種混合相(如NiO、α-Fe2O3 和 FeO)。最後,在VEH=100V條件下的橫截面高解析電子顯微鏡研究結果中,我們的確觀察到其界面結構異於其他條件下之界面(VEH=80V、120V and 150V),而為一種有效地鐵磁特性,且提供一種局部場而允許正交換偏壓場於零場冷卻下就被觀察到的條件。

English Abstract

The behavior of interfacial exchange coupling between ferromagnetic (FM) and antiferromagnetic (AFM) thin film has been extensively used to pin the magnetization in one of the layer of a magnetic spin valve or tunnel junction . In this study , to further probe the effects of the interfacial structure on exchange coupling , a series of Ni80Fe20/NixFe1-xO bilayers were created with different mixtures of ferromagnetic and antiferromagnetic phases as well as different ion deposition energies (VEH=80V、100V、120V and 150V) to investigate the possible affects of bombardment damage on the domain wall pinning . The structure and the magnetic properties of these bilayers were characterized using High resolution transmission electron microscopy (HRTEM) and Vibrating sample magnetometer (VSM) . The cross-sectional HRTEM result with the simulation of multislice have shown that Ni80Fe20 is consist of f.c.c. Ni3Fe (a = 3.545Å) and NixFe1-xO solid solution is composed of f.c.c. NiO (a = 4.177Å)、R-3c α-Fe2O3 (a = 5.035Å , c = 13.74 Å) and f.c.c. FeO (a = 4.307Å) . In the other way , According as the result of HRTEM and EELS , The dominant effect of the interfaces for VEH = 80、120V and 150V is mainly antiferromagnetic . The negative exchange bias was observed in these systems (VEH = 80、120V and 150V) . The existence ferromagnetic characteristic of interface only for the end hall voltage 100V that provides the local effective field for the positive exchange bias under zero-field cooling preparation . However , Each ferromagnetic layer (VEH=100V、120V and 150V) exhibits a columnar structure perpendicular to the film surface and the film thickness of ferromagnetic and antiferromagnetic was about 20nm and 30 nm , respectively . There is a strong linear dependence of Hc with VEH which shows that more energetic O2 ion bombardment does alter the nature of the domain wall pinning and result in different NixFe1-xO solid solution composition . Furthermore , a strong temperature dependence of exchange bias field Hex is observed in the Ni80Fe20/NixFe1-xO bilayers whose magnitude increases with decreasing temperature . A positive Hex(T) is observed when this film is zero field-cooled that is in good agreement with a (1-T/Tcrit) dependence , and a fitted Tcrit= 220±10 agree with the measured onset temperature of the exchange bias . The (1-T/Tcrit) temperature evolution of Hex is indicative of an interfacial spin imbalance biased towards AF moments that couple with the FM layer that create domain-like regions that are responsible for the measured loop shift . In brief , we present results on a nanoscale columnar Ni80Fe20/NixFe1-xO thin-film bilayers that exhibits an unusual positive exchange bias loop shift of 90 Oe at 10 K under zero field-cooled conditions. We attribute the physical origin of this odd duality of positive and negative exchange bias with different field cooling to be from a complex interfacial Ni80Fe20/NixFe1-xO structure arising from energetic ion-beam bombardment effects during the film deposition(VEH=80 V、100 V and 120 V). Therefore, we have performed a detailed structure and composition analysis of the film interface and been able to ascertain that while the NixFe1-xO solid solution is an admixture of antiferromagnetic phases (eg. NiO、α-Fe2O3 and FeO), the interface is effectively ferromagnetic in nature and provides the “local field” that permits a positive exchange bias condition in a zero applied field film preparation ( only for VEH=100 V) .

Topic Category 工學院 > 材料科學與工程學系所
工程學 > 工程學總論
Reference
  1. 1. W. H. Meiklejohn, C. P. Bean, Phys. Rev. 102 (1956) 1413.
    連結:
  2. 2. W. H. Meiklejohn, C. P. Bean Phys. Rev. 105 (1957) 904.
    連結:
  3. 9. W. C. Cain, M. H. Kryder, J. Appl. Phys. 67 (1990) 5772.
    連結:
  4. 10. B. Altuncevahir and A. R. Koymen, J. Magn. Magn. Mater. 261, (2003) 424 .
    連結:
  5. 12. J. Nogue’s and Ivan K. Schuller, J. Magn. Magn. Mater. 192 (1999) 203-232.
    連結:
  6. 13. A. H. Morrish, “The Physical Principles of magnetism”, (John Wiley & Sons, New York, 1965) p.35
    連結:
  7. 15. A. E. Berkowitz, and Kentaro Takano, J. Magn. Magn. Mater. 200 (1999) 552-570.
    連結:
  8. 18. Review: W. H. Meiklejohn, J. Appl. Phys. 33 (1962) 1328.
    連結:
  9. 19. D. Mauri, H. C. Siegmann, P. S. Bagus, E. Kay, J. Appl. Phys. 62 (1987) 3047.
    連結:
  10. 20. A. P. Malozemoff, Phys. Rev. B 35 (1987) 3679.
    連結:
  11. 21. A. P. Malozemoff, J. Appl. Phys. 63 (1988) 3874.
    連結:
  12. 22. A. P. Malozemoff, Phys. Rev. B 37 (1988) 7673.
    連結:
  13. 23. N. C. Koon, Phys. Rev. Lett. 78 (1997) 4865.
    連結:
  14. 24. T. C. Schulthess, W. H. Butler, Phys. Rev. Lett, 81 (1998) 4516.
    連結:
  15. 27. M. D. Stiles, R.D. McMichael, Phys. Rev. B 59 (1999) 3722.
    連結:
  16. 29. T. M. Hong, Phys. Rev. B 58 (1998-1) 97.
    連結:
  17. 32. R. C. O’ Handley, “Modern Magnetic Materials”, John Wiley and Sons, Inc. New York (2000).
    連結:
  18. 33. B. D. Cullity, S. R. Stock, “Elements of X-ray diffraction”, 2001.
    連結:
  19. 38. M. Julliere, Phys. Lett., 54A, (1975) 225 .
    連結:
  20. 39. J. C. Slonezewski, Phys. Rew. B39, (1989) 6995 .
    連結:
  21. 40. B. Fultz and J. M. Howe: “Transmission Electron Microscopy and Diffractometry of Materials”, Springer 2002
    連結:
  22. 42. Ludwing Reimer: “Transmission Electron Microscopy”, Springer 1997
    連結:
  23. 44. Earl J. Kirkland, Advanced computing in electron in electron microscopy (1998) , p133-138.
    連結:
  24. 2. B. Fultz and J. M. Howe: “Transmission Electron Microscopy and Diffractometry of Materials”, Springer 2002
    連結:
  25. 3. Earl J. Kirkland, Advanced computing in electron in electron microscopy (1998) , p133-138.
    連結:
  26. 3. N. C. Koon, Phys. Rev. Lett. 78 (1997) 4865.
    連結:
  27. 5. T. M. Hong, Phys. Rev. B 58 (1998-1) 97.
    連結:
  28. 6. D. Mauri, H. C. Siegmann, P. S. Bagus, E. Kay, J. Appl. Phys. 62 (1987) 3047.
    連結:
  29. 7. A. P. Malozemoff, Phys. Rev. B 35 (1987) 3679.
    連結:
  30. 8. A. P. Malozemoff, J. Appl. Phys. 63 (1988) 3874.
    連結:
  31. 9. A. P. Malozemoff, Phys. Rev. B 37 (1988) 7673.
    連結:
  32. 10. Review: W. H. Meiklejohn, J. Appl. Phys. 33 (1962) 1328.
    連結:
  33. 11. W. H. Meiklejohn, C. P. Bean Phys. Rev. 105 (1957) 904.
    連結:
  34. 第二章 參考文獻
  35. 3. R. K. Zheng, Hui. Liu, Y. Wang, and X. X. Zhang, J. Appl. Phys. 96 (2004) 5370.
  36. 4. T. J. Moran, J. M. Gallego, I. K. Schuller, J. Appl. Phys. 78 (1995) 1887.
  37. 5. A. N. Dobrynin, D. N. levlev, K. Temst P. Lievens, J. Margueritat, J. Gonzalo, C. N. Afonso, S. Q. Zhou, A. Vantomme, E. Piscopiello, and G. Van Tendeloo, Appl. Phys. Lett. 87, (2005) 012501 .
  38. 6. J. Nogue’s, C. Leighton and Ivan K. Schuller, Phys. Rev. B 61 (2000-II) 1315.
  39. 7. X. Ke, M. S. Rzchowski, L. J. Belenky, and C. B. Eom, Appl. Phys. Lett. 84, (2004) 5458 .
  40. 8. P. J. van der Zaag, R.M. Wolf, A.R. Ball, C. Bordel, L. F. Feiner, and R. Jungblut, J. Magn. Magn. Mater. 148 (1995) 346.
  41. 11. 金重勳主編,”Handbook of Magnetic Technologies”,中華民國磁性技術協會,(2002).
  42. 14. W. L. Roth, J. Appl. Phys. 31 (1960) 200.
  43. 16. Kentaro Takano, R. H. Kodama, A. E. Berkowitz, W. Cao, G. Thomas, Phys. Rev. Lett. 79 (1997) 1130.
  44. 17. Susana Gota, Martine Gautier-Soyer, and Maurizio Sacchi, Phys. Rev. B, 64, (2001) 224407-1.
  45. 25. Kentaro Takano, R. H. Kodama, A. E. Berkowitz, W. Cao, G. Thomas, J. Appl. Phys. 83 (1998) 6888.
  46. 26. M. Kiwi, J. Mejı´a-Lo´pez, R. Portugal, and R. Ramı´rez, Europhys. Lett. 48, 573 (1999).
  47. 28. A. S. Carrico, R. E. Camley, R. L. Stamps, Phys. Rev. B 50 (1994) 13453.
  48. 30. J. Nogue’s , D. Lederman, T. J. Moran, and Ivan K. Schuller, Phys. Rev. Lett. 76. (1996) 4624.
  49. 31. E. M. Lecin et al., Phase Diagram for Ceramists, Amer. Cer. Soc., (1964).
  50. 34. J. C. A. Huang, T. E. Wang, C. C. Yu, Y. M. Hu, P. B. Lee, and M. S. Yang, J. Cryst. Growth. 171, 442, 1997.
  51. 35. M. N. Baibich, J. M. Broto, A. Fert, F. Nguyen Van Dau, and F. Pctroff, Phys. Rev. Lett. 61 (1988) 2472.
  52. 36. W. Thomson, Proc. Roy. Soc.,8, (1857) 546 .
  53. 37. L. H. Chen, S. Jin,T. Tiefel, and R. Ramesh, J. Mater. Res., 9, (1994) 1134 .
  54. 41. 陳力俊 等箸,材料電子顯微鏡學,國科會精儀中心
  55. 43. JEMS software package that is developed by Pierre Stadelmann, http://cimesg1.epfl.ch/CIOL/ems.html
  56. 第三章 參考文獻
  57. 1. 中興大學材料工程學系碩士論文,鎳鐵/鎳鐵氧化物雙層薄膜之結構及磁性研究,曾譯民,民94年。
  58. 4. JEMS software package that is developed by Pierre Stadelmann, http://cimesg1.epfl.ch/CIOL/ems.html
  59. 5. 陳建人, “真空技術與應用”, 行政院國家科學委員會精密儀器發展中心, 2000.
  60. 6. 雙離子束濺鍍系統操作手冊.
  61. 第四章 參考文獻
  62. 1. k. W.Lin, Y. M. Tzeng, Z. Y. Guo, C. Y. Liu, and J. van Lierop, in press (2006).
  63. 2. J. Nogue’s , D. Lederman, T. J. Moran, and Ivan K. Schuller, Phys. Rev. Lett. 76. (1996) 4624.
  64. 4. M. Kiwi, J. Mejı´a-Lo´pez, R. Portugal, and R. Ramı´rez, Europhys. Lett. 48, 573 (1999).
  65. 12. H. Ouyang, K.-W. Lin, C.-C. Liu, Y.-M. Tzeng, Z.-Y. Guo, Shen-Chuan Lo, and J. van Lierop, unpublished results.
  66. 13. Susana Gota, Martine Gautier-Soyer, and Maurizio Sacchi, Phys. Rev. B, 64, (2001) 224407-1.
  67. 14. J. B. Yi, J. Ding, Z. L. Zhao, and B. H. Liu, J. Appl. Phys. 97 (2005) 10K306.
  68. 15. E. Fulcomer and S. H. Charap, J. Appl. Phys. 43. (1972) 4190.
  69. 16. 金重勳主編,”Handbook of Magnetic Technologies”,中華民國磁性技術協會,(2002) P117、P204
  70. 17. J. Nogue’s, C. Leighton and Ivan K. Schuller, Phys. Rev. B 61 (2000-II) 1315.
Times Cited
  1. 林逸華(2009)。控制氧含量對鎳鈷/鎳鈷氧化物雙層薄膜之微結構與磁性質的影響。中興大學材料科學與工程學系所學位論文。2009。1-154。 
  2. 鍾杉慧(2009)。鉑/鈷/氧化鎳奈米多層膜之結構與磁性質之研究。中興大學材料科學與工程學系所學位論文。2009。1-130。 
  3. 黃以陞(2013)。改變轟擊電壓與氧含量對於MgO/NiO/Ni3Fe與SiO2/NiO/Ni3Fe微結構與交換偏壓的影響。清華大學材料科學工程學系學位論文。2013。1-144。 
  4. 戴永清(2011)。氧化鎳/鎳鐵磊晶雙層膜交換偏壓研究。清華大學材料科學工程學系學位論文。2011。1-409。 
  5. 蘇群皓(2008)。奈米尺寸Co/Pt多層膜垂直異向性探討。中興大學材料科學與工程學系所學位論文。2008。1-126。
  6. 韓侑宏(2010)。藉由第一原理分析CrSi2(核)/SiO2(殼)奈米電纜異常的鐵磁性質與氧化鎳薄膜成長研究。清華大學材料科學工程學系學位論文。2010。1-174。