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題名 單晶二維凡得瓦 Fe3GeTe2的電流沿不同晶格軸向電性量測
Electrical measurements of two-dimensional van der Waals Fe3GeTe2 single crystals with current along different crystal axes作者 張仁豪
Jhang, Ren-Hao貢獻者 李尚凡
Lee, Shang-Fan
張仁豪
Jhang, Ren-Hao關鍵詞 二維磁性材料
磁阻
異常霍爾效應
2D magnetic material
Fe3GeTe2
Magnetoresistance
Anomalous hall effect日期 2023 上傳時間 1-Sep-2023 16:28:53 (UTC+8) 摘要 二維凡得瓦鐵磁材料Fe_3 GeTe_2(FGT)具有高居禮溫度、強垂直異向性、金屬導體特性和自旋軌道耦合等優良的應用性質。因此，本實驗使用電傳輸方法研究FGT薄膜的基本電性與磁性，基於相關文獻的理論預測，嘗試藉由改變電流密度改變FGT薄膜磁性。另外，由於相關文獻報導FGT凡得瓦層間具有反鐵磁相與鐵磁相的競爭，因此本實驗也對單晶FGT不同晶格軸向電阻、磁阻進行量測，以探討其導電機制是否有自旋相關性。本實驗所使用的單晶FGT塊材由化學氣相傳輸法(Chemical Vapor Transport, CVT)生長。使用傳統的機械剝離(Mechanical Exfoliation)方法製備FGT薄膜，並使用微影、電子束和濺鍍等製程方法在薄膜表面製作電極，由於FGT薄膜表面存在氧化問題，因此採用離子研磨的方式，去除薄膜與電極間的氧化層。此外，為了能在單晶FGT各晶格軸向接上電極，本實驗使用雙束聚焦離子束(Dual beam focus ion beam)來製備樣品。本實驗使用四點量測方法成功測得FGT薄膜的基本磁阻、異常霍爾效應，數據顯示，FGT薄膜具有很強的垂直異向性。另外本實驗也通過改變電流密度來增加電流誘導的自旋軌道轉矩來傾斜FGT的磁矩。為了減少電流焦耳熱效應的影響，本實驗使用脈衝電流進行實驗。然而，根據數據顯示，脈衝電流仍無法有較排除熱效應。在單晶FGT塊材的電性量測中，我們發現在晶格C軸方向電阻率除了在居禮溫度(210K)附近發生相變化外，還在約80K時出現了相變化，且在不同的晶格軸向的各相異性磁阻有類似的表現行為。電阻率隨溫度的變化關係中，C軸方向電阻率約是A軸(凡得瓦層面內)電阻率的4到5倍。
Fe3GeTe2 (FGT) is a two-dimensional van der Waals ferromagnetic material known for its high Curie temperature, strong perpendicular magnetic anisotropy, metallic conductivity, and spin-orbit coupling. In this study, we employed electrical transport measurements to investigate the fundamental electric and magnetic properties of FGT thin films. Building upon theoretical predictions from relevant literature, we attempted to modulate the magnetic properties of FGT films by varying the current density. Additionally, due to the reported competition between antiferromagnetic and ferromagnetic phases within the van der Waals layers of FGT, we measured the electrical resistance and magnetoresistance along different crystallographic axes of single-crystal FGT to explore potential spin-related conduction mechanisms. The single-crystal FGT samples used in this experiment were grown using the chemical vapor transport (CVT) method. FGT thin films were prepared through conventional mechanical exfoliation, and electrode patterns were fabricated on the film surface using techniques such as photolithography or electron beam lithography and followed by sputtering deposition. To address the oxidation issue on the FGT film surface, ion milling was employed to remove the oxide layer between the film and the electrodes. Moreover, to attach electrodes to different crystallographic axes of the single-crystal FGT, a dual-beam focused ion beam system was utilized for sample preparation. Using the four-point measurement method, we successfully measured the basic magnetoresistance and anomalous Hall voltage curves of the FGT thin films, demonstrating a pronounced out-of-plane anisotropy. Furthermore, by increasing the current-induced spin-orbit torque through the manipulation of current density, we were able to incline the magnetization of FGT. To mitigate the effects of Joule heating, pulsed current was employed in the experiments. However, the data indicated that even with pulsed current, the thermal effects could not be fully eliminated. In the electrical characterization of single-crystal FGT, we observed a phase transition in the resistivity along the crystallographic C-axis near the Curie temperature (210 K) and at approximately 80 K. Additionally, similar behaviors were observed in the magnetoresistance of different crystallographic axes, indicating distinct phase transitions. Depending on the temperature, the C-axis resistivity is about 4 to 5 times of the in-plane resistivity.參考文獻 [1] K. Kim et al., "Large anomalous Hall current induced by topological nodal lines in a ferromagnetic van der Waals semimetal," (in eng), Nat Mater, vol. 17, no. 9, pp. 794-799, Sep 2018, doi: 10.1038/s41563-018-0132-3.[2] K. Yasakau, "Application of AFM-Based Techniques in Studies of Corrosion and Corrosion Inhibition of Metallic Alloys," Corrosion and Materials Degradation, vol. 1, no. 3, pp. 345-372, 2020. [Online]. Available: https://www.mdpi.com/2624-5558/1/3/17.[3] S. Meltem, "Focused Ion Beams (FIB) — Novel Methodologies and Recent Applications for Multidisciplinary Sciences," in Modern Electron Microscopy in Physical and Life Sciences, J. Milos and K. Robert Eds. Rijeka: IntechOpen, 2016, p. Ch. 6.[4] N. Nagaosa, J. Sinova, S. Onoda, A. H. MacDonald, and N. P. Ong, "Anomalous Hall effect," Reviews of Modern Physics, vol. 82, no. 2, pp. 1539-1592, 05/13/ 2010, doi: 10.1103/RevModPhys.82.1539.[5] Ø. Johansen, V. Risinggård, A. Sudbø, J. Linder, and A. Brataas, "Current Control of Magnetism in Two-Dimensional ${\\mathrm{Fe}}_{3}{\\mathrm{GeTe}}_{2}$," Physical Review Letters, vol. 122, no. 21, p. 217203, 05/31/ 2019, doi: 10.1103/PhysRevLett.122.217203.[6] C. 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Zhang et al., "Gigantic Current Control of Coercive Field and Magnetic Memory Based on Nanometer-Thin Ferromagnetic van der Waals Fe3GeTe2," Advanced Materials, vol. 33, no. 4, p. 2004110, 2021, doi: https://doi.org/10.1002/adma.202004110.[11] K. S. Novoselov et al., "Electric field effect in atomically thin carbon films," (in eng), Science, vol. 306, no. 5696, pp. 666-9, Oct 22 2004, doi: 10.1126/science.1102896.[12] N. D. Mermin and H. Wagner, "Absence of Ferromagnetism or Antiferromagnetism in One- or Two-Dimensional Isotropic Heisenberg Models," Physical Review Letters, vol. 17, no. 22, pp. 1133-1136, 11/28/ 1966, doi: 10.1103/PhysRevLett.17.1133.[13] C. Si, J. Zhou, and Z. Sun, "Half-Metallic Ferromagnetism and Surface Functionalization-Induced Metal–Insulator Transition in Graphene-like Two-Dimensional Cr2C Crystals," ACS Applied Materials & Interfaces, vol. 7, no. 31, pp. 17510-17515, 2015/08/12 2015, doi: 10.1021/acsami.5b05401.[14] R. Shidpour and M. 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Shi, "Proximity-Induced Ferromagnetism in Graphene Revealed by the Anomalous Hall Effect," Physical Review Letters, vol. 114, no. 1, p. 016603, 01/07/ 2015, doi: 10.1103/PhysRevLett.114.016603.[23] C. Gong et al., "Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals," (in eng), Nature, vol. 546, no. 7657, pp. 265-269, Jun 8 2017, doi: 10.1038/nature22060.[24] B. Huang et al., "Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit," (in eng), Nature, vol. 546, no. 7657, pp. 270-273, Jun 7 2017, doi: 10.1038/nature22391.[25] M. Bonilla et al., "Strong room-temperature ferromagnetism in VSe(2) monolayers on van der Waals substrates," (in eng), Nat Nanotechnol, vol. 13, no. 4, pp. 289-293, Apr 2018, doi: 10.1038/s41565-018-0063-9.[26] D. J. O’Hara et al., "Room Temperature Intrinsic Ferromagnetism in Epitaxial Manganese Selenide Films in the Monolayer Limit," Nano Letters, vol. 18, no. 5, pp. 3125-3131, 2018/05/09 2018, doi: 10.1021/acs.nanolett.8b00683.[27] H. Zhang et al., "Itinerant ferromagnetism in van der Waals ${\\mathrm{Fe}}_{5\\ensuremath{-}x}{\\mathrm{Ge}\\mathrm{Te}}_{2}$ crystals above room temperature," Physical Review B, vol. 102, no. 6, p. 064417, 08/19/ 2020, doi: 10.1103/PhysRevB.102.064417.[28] Y. Deng et al., "Gate-tunable room-temperature ferromagnetism in two-dimensional Fe(3)GeTe(2)," (in eng), Nature, vol. 563, no. 7729, pp. 94-99, Nov 2018, doi: 10.1038/s41586-018-0626-9.[29] X. Wang et al., "Current-driven magnetization switching in a van der Waals ferromagnet Fe3GeTe2," Science Advances, vol. 5, no. 8, p. eaaw8904, 2019, doi: doi:10.1126/sciadv.aaw8904.[30] I. Shin et al., "Spin–Orbit Torque Switching in an All-Van der Waals Heterostructure," Advanced Materials, vol. 34, no. 8, p. 2101730, 2022, doi: https://doi.org/10.1002/adma.202101730.[31] M. N. Baibich et al., "Giant Magnetoresistance of (001)Fe/(001)Cr Magnetic Superlattices," Physical Review Letters, vol. 61, no. 21, pp. 2472-2475, 11/21/ 1988, doi: 10.1103/PhysRevLett.61.2472.[32] H. Ebert, A. Vernes, and J. Banhart, "Magnetoresistance, Anisotropic," in Encyclopedia of Materials: Science and Technology, K. H. J. Buschow, R. W. Cahn, M. C. Flemings, B. Ilschner, E. J. Kramer, S. Mahajan, and P. Veyssière Eds. Oxford: Elsevier, 2001, pp. 5079-5083.[33] B. Raquet, M. Viret, E. Sondergard, O. Cespedes, and R. Mamy, "Electron-magnon scattering and magnetic resistivity in $3d$ ferromagnets," Physical Review B, vol. 66, no. 2, p. 024433, 07/25/ 2002, doi: 10.1103/PhysRevB.66.024433.[34] R. P. Khosla and J. R. Fischer, "Magnetoresistance in Degenerate CdS: Localized Magnetic Moments," Physical Review B, vol. 2, no. 10, pp. 4084-4097, 11/15/ 1970, doi: 10.1103/PhysRevB.2.4084.[35] R. M. Langford, "Focused Ion Beam Systems: Application to Micro- and Nanofabrication," in Encyclopedia of Materials: Science and Technology, K. H. J. Buschow, R. W. Cahn, M. C. Flemings, B. Ilschner, E. J. Kramer, S. Mahajan, and P. Veyssière Eds. Oxford: Elsevier, 2010, pp. 1-13.[36] B. Chen et al., "Magnetic Properties of Layered Itinerant Electron Ferromagnet Fe3GeTe2," Journal of the Physical Society of Japan, vol. 82, no. 12, p. 124711, 2013/12/15 2013, doi: 10.7566/JPSJ.82.124711.[37] https://www.sunda-optical.com.tw/products_detail/25.htm[38] https://lnf-wiki.eecs.umich.edu/wiki/Atomic_force_microscopy[39] https://www.cpfs.mpg.de/2651362/chemical-vapor-transport 描述 碩士
國立政治大學
應用物理研究所
110755009資料來源 http://thesis.lib.nccu.edu.tw/record/#G0110755009 資料類型 thesis dc.contributor.advisor 李尚凡 zh_TW dc.contributor.advisor Lee, Shang-Fan en_US dc.contributor.author (Authors) 張仁豪 zh_TW dc.contributor.author (Authors) Jhang, Ren-Hao en_US dc.creator (作者) 張仁豪 zh_TW dc.creator (作者) Jhang, Ren-Hao en_US dc.date (日期) 2023 en_US dc.date.accessioned 1-Sep-2023 16:28:53 (UTC+8) - dc.date.available 1-Sep-2023 16:28:53 (UTC+8) - dc.date.issued (上傳時間) 1-Sep-2023 16:28:53 (UTC+8) - dc.identifier (Other Identifiers) G0110755009 en_US dc.identifier.uri (URI) http://nccur.lib.nccu.edu.tw/handle/140.119/147299 - dc.description (描述) 碩士 zh_TW dc.description (描述) 國立政治大學 zh_TW dc.description (描述) 應用物理研究所 zh_TW dc.description (描述) 110755009 zh_TW dc.description.abstract (摘要) 二維凡得瓦鐵磁材料Fe_3 GeTe_2(FGT)具有高居禮溫度、強垂直異向性、金屬導體特性和自旋軌道耦合等優良的應用性質。因此，本實驗使用電傳輸方法研究FGT薄膜的基本電性與磁性，基於相關文獻的理論預測，嘗試藉由改變電流密度改變FGT薄膜磁性。另外，由於相關文獻報導FGT凡得瓦層間具有反鐵磁相與鐵磁相的競爭，因此本實驗也對單晶FGT不同晶格軸向電阻、磁阻進行量測，以探討其導電機制是否有自旋相關性。本實驗所使用的單晶FGT塊材由化學氣相傳輸法(Chemical Vapor Transport, CVT)生長。使用傳統的機械剝離(Mechanical Exfoliation)方法製備FGT薄膜，並使用微影、電子束和濺鍍等製程方法在薄膜表面製作電極，由於FGT薄膜表面存在氧化問題，因此採用離子研磨的方式，去除薄膜與電極間的氧化層。此外，為了能在單晶FGT各晶格軸向接上電極，本實驗使用雙束聚焦離子束(Dual beam focus ion beam)來製備樣品。本實驗使用四點量測方法成功測得FGT薄膜的基本磁阻、異常霍爾效應，數據顯示，FGT薄膜具有很強的垂直異向性。另外本實驗也通過改變電流密度來增加電流誘導的自旋軌道轉矩來傾斜FGT的磁矩。為了減少電流焦耳熱效應的影響，本實驗使用脈衝電流進行實驗。然而，根據數據顯示，脈衝電流仍無法有較排除熱效應。在單晶FGT塊材的電性量測中，我們發現在晶格C軸方向電阻率除了在居禮溫度(210K)附近發生相變化外，還在約80K時出現了相變化，且在不同的晶格軸向的各相異性磁阻有類似的表現行為。電阻率隨溫度的變化關係中，C軸方向電阻率約是A軸(凡得瓦層面內)電阻率的4到5倍。 zh_TW dc.description.abstract (摘要) Fe3GeTe2 (FGT) is a two-dimensional van der Waals ferromagnetic material known for its high Curie temperature, strong perpendicular magnetic anisotropy, metallic conductivity, and spin-orbit coupling. In this study, we employed electrical transport measurements to investigate the fundamental electric and magnetic properties of FGT thin films. Building upon theoretical predictions from relevant literature, we attempted to modulate the magnetic properties of FGT films by varying the current density. Additionally, due to the reported competition between antiferromagnetic and ferromagnetic phases within the van der Waals layers of FGT, we measured the electrical resistance and magnetoresistance along different crystallographic axes of single-crystal FGT to explore potential spin-related conduction mechanisms. The single-crystal FGT samples used in this experiment were grown using the chemical vapor transport (CVT) method. FGT thin films were prepared through conventional mechanical exfoliation, and electrode patterns were fabricated on the film surface using techniques such as photolithography or electron beam lithography and followed by sputtering deposition. To address the oxidation issue on the FGT film surface, ion milling was employed to remove the oxide layer between the film and the electrodes. Moreover, to attach electrodes to different crystallographic axes of the single-crystal FGT, a dual-beam focused ion beam system was utilized for sample preparation. Using the four-point measurement method, we successfully measured the basic magnetoresistance and anomalous Hall voltage curves of the FGT thin films, demonstrating a pronounced out-of-plane anisotropy. Furthermore, by increasing the current-induced spin-orbit torque through the manipulation of current density, we were able to incline the magnetization of FGT. To mitigate the effects of Joule heating, pulsed current was employed in the experiments. However, the data indicated that even with pulsed current, the thermal effects could not be fully eliminated. In the electrical characterization of single-crystal FGT, we observed a phase transition in the resistivity along the crystallographic C-axis near the Curie temperature (210 K) and at approximately 80 K. Additionally, similar behaviors were observed in the magnetoresistance of different crystallographic axes, indicating distinct phase transitions. Depending on the temperature, the C-axis resistivity is about 4 to 5 times of the in-plane resistivity. en_US dc.description.tableofcontents 第一章 緒論 1第一節 研究動機 3第二章 背景理論 5第一節 磁阻(Magnetoresistance)[8] 5第二節 異向性磁阻(Anisotropic Magnetoresistance, AMR)[32] 6第三節 異常霍爾效應(Anomalous Hall Effect, AHE) 7第三章 文獻探討 8第四章 樣品製備與儀器 23第一節 化學氣相傳輸方法製備Fe3GeTe2晶體 23第二節 機械剝離製備薄膜 24一、清潔FGT塊材表面 24二、清洗二氧化矽基板(SiO2 :300nm/Intrinsic Silicon) 24三、準備所需的膠帶和PDMS stamp 24四、機械剝離和轉移樣品 25第三節 紫外光微影製程 26一、製程前的圖案設計及薄膜選擇 26二、微影製程介紹以及使用機台、製程參數 27第四節 濺鍍 28一、真空濺鍍原理 28二、沉積金屬薄膜、舉離 30第五節 電子束微影製程/表面處理 31電子束微影製程介紹 31第六節 雙束聚焦離子束Dual Beam Focus Ion Beam[35] 33第七節 FGT樣品電性量測 38第八節 四點量測 39第九節 薄膜厚度量測：原子力顯微鏡(AFM) 40第五章 實驗結果及數據討論 42第一節 FGT薄膜電阻率對溫度與薄膜厚度關係 42第二節 FGT薄膜異常霍爾效應/居禮溫度與厚度關係 48第三節 電流誘導SOT控制FGT薄膜磁性 54第四節 FGT塊材磁阻數據 63第五節 FGT塊材異常霍爾效應數據 68第六節 FGT塊材電阻對溫度變化數據 74第七節 FGT塊材SEM-EDS成分分析 77第八節 FGT塊材&粉末X-Ray Diffraction分析 81結論 83參考資料 85 zh_TW dc.format.extent 7606657 bytes - dc.format.mimetype application/pdf - dc.source.uri (資料來源) http://thesis.lib.nccu.edu.tw/record/#G0110755009 en_US dc.subject (關鍵詞) 二維磁性材料 zh_TW dc.subject (關鍵詞) 磁阻 zh_TW dc.subject (關鍵詞) 異常霍爾效應 zh_TW dc.subject (關鍵詞) 2D magnetic material en_US dc.subject (關鍵詞) Fe3GeTe2 en_US dc.subject (關鍵詞) Magnetoresistance en_US dc.subject (關鍵詞) Anomalous hall effect en_US dc.title (題名) 單晶二維凡得瓦 Fe3GeTe2的電流沿不同晶格軸向電性量測 zh_TW dc.title (題名) Electrical measurements of two-dimensional van der Waals Fe3GeTe2 single crystals with current along different crystal axes en_US dc.type (資料類型) thesis en_US dc.relation.reference (參考文獻) [1] K. Kim et al., "Large anomalous Hall current induced by topological nodal lines in a ferromagnetic van der Waals semimetal," (in eng), Nat Mater, vol. 17, no. 9, pp. 794-799, Sep 2018, doi: 10.1038/s41563-018-0132-3.[2] K. Yasakau, "Application of AFM-Based Techniques in Studies of Corrosion and Corrosion Inhibition of Metallic Alloys," Corrosion and Materials Degradation, vol. 1, no. 3, pp. 345-372, 2020. [Online]. Available: https://www.mdpi.com/2624-5558/1/3/17.[3] S. Meltem, "Focused Ion Beams (FIB) — Novel Methodologies and Recent Applications for Multidisciplinary Sciences," in Modern Electron Microscopy in Physical and Life Sciences, J. Milos and K. Robert Eds. Rijeka: IntechOpen, 2016, p. Ch. 6.[4] N. Nagaosa, J. Sinova, S. Onoda, A. H. MacDonald, and N. P. Ong, "Anomalous Hall effect," Reviews of Modern Physics, vol. 82, no. 2, pp. 1539-1592, 05/13/ 2010, doi: 10.1103/RevModPhys.82.1539.[5] Ø. Johansen, V. Risinggård, A. Sudbø, J. Linder, and A. 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