Center for Neutron Beam Applications

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1 Center for Neutron Beam Applications
National Central University 台灣在澳洲ANSTO的 中子束實驗機會 (95年10月31日) Wen-Hsien Li (李文献) Center for Neutron Beam Applications National Central University

2 2 thermal guides + 2 cold guides
Bragg Institute at ANSTO 位於雪梨西南30公里處，時差2小時，飛行時間9小時 Reactor Hall Control room Office building (Taiwan team office) Guide Hall 2 thermal guides + 2 cold guides

3 Opal neutron beam instrument mascots
Echidna (HRPD) Platypus (Reflect) Quokka (SANS) Wombat (HIPD) Neutron diffraction Large scale structures Inelastic neutron scattering Taipan (Triple Axis) Kowari (Resid. Stress) Koala (QLD) Sika (Cold-Triple Axis) Pelican (TOF-PAS)

4 Instrument Feb. 2007 Apr. 2007 Jun. 2007 Sept. 2007 Aug. 2007
First neutrons - start of safety commissioning Source Licence from ARPANSA Start "Friendly-User" Experiments Start peer-reviewed formal User Program Echidna High-Resolution Powder Diffractometer Sept. 2006 Jan. 2007 Feb. 2007 Apr. 2007 Koala Quasi-Laue Diffractometer Nov. 2006 Kowari Strain Scanner Mar. 2007 Jun. 2007 Platypus Neutron Reflectometer Wombat High-Intensity Powder Diffractometer Taipan Thermal 3-Axis Spectrometer Sept. 2007 Quokka Small-Angle Neutron Scattering Aug. 2007 (Crystalline structure) (Magnetic thin film) (Magnetic structure) (Excitations) (Large molecule)

5 Spin-echo Inelastic K-space Analyzer
Taiwan SIKA-project Formosan sika deer Spin-echo Inelastic K-space Analyzer Triple-axis spectrometer → Inelastic scattering, analyzing k-space. Ultra-high energy resolution → resonance spin echo technique Cold TAS : E ~ 0.1 to 1 meV With RSET : E ~ 1 to 100 eV (optional) A spin-echo cold neutron triple-axis spectrometer

6 A cold-neutron triple-axis spectrometer at ANSTO
SIKA A cold-neutron triple-axis spectrometer at ANSTO 熱三軸 2007 Sept. SIKA Taipan Cold Triple Axis Reactor face 冷三軸 2010 spring SIKA 計畫時程 (2006, 09修訂) 2009 2008 2007 2006 (概念設計) (工程設計) (採購) (組裝) (測試) 1 Å = 82 meV 2 Å = 20.5 meV 4 Å = 5 meV 6.2 Å = 2.3 meV

7 Layout of a triple-axis spectrometer
Filter selector Beam shutter Collimator exchanger Monochromator Sample table Analyser Beam stop Detector Beam aperture Beam tube Monochromator drum Analyzer-detector system 1st axis 2nd axis 3rd axis

8 核反應爐源 中子束特性

9 中子源與中子束特性 ˙核反應器中子源: 穩態，能量依Maxwellian分佈 H2O/D2O/石墨減能至meV範圍 ˙冷中子源:
爐内增設致冷器(液態氫) ˙加速器中子源: 脈衝式，瞬時通量較高 ˙對樣品穿透力: 除少數元素(如Gd、Cd、Sm、B)外， 基本上全然穿透 ˙Average flux 1MW spallation source ≈ 10MW reactor source

10 中子散射作用力與中子束能量 ˙散射作用力: 中子–原子核:強交互作用力 (見到原子核，散射機率並非隨原子序增加而增大)  偵測原子核位置
 晶體結構 中子自旋–未成對電子自旋:磁偶矩交互作用力  偵測未成對電子自旋  磁結構 ˙能量:meV範圍(適合探討凝體系統動力現象) 超熱中子: 200 meV, Å 熱中子: meV, 2 Å 冷中子: meV, Å

11 中子束基本功能 ˙為一非破壞性探測的工具。 ˙能深入系統的內部。 ˙目前唯一能探測磁性結構的工具 → 磁性材料。 ˙在重原子間判定輕原子
→ 生化分子裡氫原子的測定。 ˙動力組態探討。 → 所具能量與動力激發子相當。

12 鋰二次電池電極材料 Li(Mn1-xCox)O4 結構與磁性探討

13 變溫高解析度中子繞射譜圖 Structural change induced capacity loss. 200 & 250 K間
結構相轉變

14 Jahn-Teller distortion
Li Electronic configuration discharge reconfiguration distortion Reconfiguration of the band structure, results in a reduction of the carries density.  Capacity loss.

15 Stabilization of crystal structure
Li0.99(Mn0.976Co0.024)2O4.036 λ = Å 15'-20' -7' No structural distortion was observed bet. 9 & 300 K A 2.5% Co-doping stabilizes the crystalline structure.

16 Two-step short-range Mn spin ordering
Magnetic unit cell I1.4K - I80K Ordering temperatures for the two components: at 90 K & 50 K Two separate magnetic components Separate ordering of Mn3+ and Mn4+.

17 Cluster structure of Mn3+ and Mn4+
Mn3+ (electron-rich region) 被 Mn4+ (hole-rich region) 所環繞形成叢集的型態。 並非Mn4+和Mn3+交替排列。 PRL 81, 4660 (1998)

18 Ferromagnetic clusters antiferromagnetic coupling
and antiferromagnetic coupling in lightly Cr-doped (Bi/Ca)MnO3

19 Two polycrystalline samples
BixCa1-xMn0.95Cr0.05O3 x=0.4 and 0.5

20 Motivation Measurements Search for
1. FM/AFM clusters/long range orders 2. Spin fluctuations at high temperatures Measurements 1. High resolution neutron powder diffraction 2. Magnetic susceptibility 3. Magnetic neutron diffraction 4. Resistivity 5. Specific heat

21 Structure and Composition determination
BCMCO Structure and Composition determination Neutron The neutron powder diffraction patterns was taken at various temperatures. This plot shows the high resolution neutron powder diffraction data taken at NIST using the BT-1 diffractometer.

22 Jahn-Teller distortion
BCMCO Jahn-Teller distortion Shown here are the variations of the cell volume and lattice parameters with temperature. An inflection at around 280 K is clearly seen in both plots, showing the occurrence of Jahn-Teller distortion.

23 Transport behavior BCMCO
Temperature dependence of 1/T1/4 of electric resistivity of Bi0.4Ca0.6Mn0.95Cr0.05O3. This figure plots follow the Mott’s variable-range hoping (VRH) of the charge carriers.ρVHR= ρ0exp(T0/T)1/4. The fitting parameter T0(0 T)= 49 K, ρ0=7.8(7)×10-7 Ω-cm. An anomaly was found at around 280 K.

24 Magnetic susceptibility
BCMCO Magnetic susceptibility μest= 4.43μB

25 Neutron magnetic diffraction
BCMCO Neutron magnetic diffraction Magnetic diffraction pattern + model fit

26 Magnetic Structure Bi0.4Ca0.6Mn0.95Cr0.05O3 BCMCO c c b b a a
90° 45° a b c 90° 45° Mn3+ Mn4+ Mn3+:Mn4+=10:6 <μ> = 1.78(1) μB Bi0.4Ca0.6Mn0.95Cr0.05O3

27 Magnetic Structure Bi0.5Ca0.5Mn0.95Cr0.05O3 BCMCO c b a

28 Order parameters BCMCO Bi0.5Ca0.5Mn0.95Cr0.05O3
TN=80 K TN=90 K

29 Pr-O-Pr 鍵長與鍵角對 PrBa2Cu3O6+x 磁性的影響
奈米物性實驗室 Pr-O-Pr 鍵長與鍵角對 PrBa2Cu3O6+x 磁性的影響

30 Basic physical properties of RBa2Cu3O6+x(R123)
超導層 稀土層 電洞庫層 隔離層 R=稀土元素 R + 2(BaO) + 2(CuO2) + CuOx 導電性及磁性均受控於x RBa2Cu3O7: 98K超導體 (除R=Pr) R反鐵磁有序(TN<1K) 但PrBa2Cu3O7: TC=0K (無超導電性) TN(Pr)=17K TN(Cu)=270K

31 高解析度中子繞射譜圖 l q PrBa Cu O = 1.5402 A Counts / min Scattering angle 2
20 40 60 80 100 120 140 160 200 400 600 800 1000 1200 1400 1600 1800 2000 o 15'-20'-7' 1005 1004 1003 1002 PrBa 2 Cu 3 O 6+y l = A Counts / min Scattering angle 2 q

32 高解析度中子繞射譜圖 ˙4組譜圖明顯不一樣: 源於氧含量不同 ˙是否可以y>1: Cu-O鍊結構被破壞

33 Crystal structure & nuclear density contours
PrBa2Cu3O6.338 Cu(2) Pr c 76.49°(7) 2.4882(12) Å 103.51°(7) b O(2) a 2.7991(9) Å Ba O(1) Cu(1) c O(4) a Center at (1/2 1/2 0) Center at (1/2 1/2 1/2)

34 Nuclear density contours
PrBa2Cu3O6.338 a b Center (1/2, 1/2, 0) (1/2, 1/2, 0.19) (1/2, 1/2, 0.352) (1/2, 1/2, 1/2)

35 Polymer intercalated FeOCl
奈米物性實驗室 Polymer intercalated FeOCl

36 導電高分子系統 ˙ 系統 1. FeOCl 2. FeOCl + PANI 3. FeOCl + Na 4. FeOHPO4 ˙探討物理量
1. Structural change induced by intercalation 2. Magnetic competition 3. Non-collinear Fe magnetic ordering 4. Q2D bilayered magnetic coupling

37 Magnetic interactions between Fe-O-Fe
• Direct exchange (DE): Fe–Fe → Ferromagnetic • Superexchange (SE): Mediated through O between the Fe ions Fe–O–Fe → Antiferromagnetic • Competition between FMDE & AFMSE: Non-collinear spin arrangement

38 Spin arrangement of Fe in Van-der-Waals gaped FeOCl
Along b: antiparallel Magnetic modulation vector K=(2/7 1/2 1/2) Van-der-Waals gap Direct results of competition between FMDE & AFMSE

39 Quasi-2D ordering of the Fe spins in polyaniline-intercalated FeOCl
1. Coupled bilayered quasi-2D magnetic scattering profile. 2. No magnetic correlation between the adjacent bilayers. c Magnetic modulation vector K=(1/3 1/2) a Along b: antiparallel

40 熱效應 對鄰苯二酚加氧酵素 活性與結構組態的影響
中央大學奈米物性實驗室 熱效應 對鄰苯二酚加氧酵素 活性與結構組態的影響

41 Subjects 主題 1. 溫度對酵素活性的影響(熱穩定性) 工具 1. Biological analysis 系統
2. 溫度對酵素結構組態的效應 工具 1. Biological analysis 2. Activation analysis 3. Small angle neutron scattering 系統 1. C23Onap(SH1) --- 台灣 2. C23Onap(NCIB9816-4) --- 美國

42 鄰苯二酚加氧酵素（catechol dioxygenase, C23O)
酵素的催化功能---協助分解苯環 鄰苯二酚加氧酵素（catechol dioxygenase, C23O) 苯環的分解 O2 OH C23O Napthalene Catechol CHO COOH • 一般而言 最適催化溫度 ~55 ℃ 酵素穩定性 < 25 ℃ •酵素的組態----常以單晶X-射線繞射實驗訂之 由數個次單位體（subunit）所組成

43 C23Otol(mt-2)的次單位體結構圖 La= 0.8 Lc Lb = 0.6 Lc Lc Lb
Kita et al. Structure 7, 25(1999)

44 C23Otol(mt-2)的分子組態與尺度 66 Å 94 Å b c a ~ 94 Å (單晶)
~ 94 Å (單晶) 94 Å 66 Å c b a da : db : dc = 48 Å : 66 Å : 94 Å = 0.5 : 0.7 : 1 Kita et al. structure 7, 25(1999)

45 C23Onap(SH1)在各溫度下的活性隨時間變化圖
殘餘活性與時間的關係 R(t)=R0 exp{(t/t0)α} R(t):殘餘活性 R0 :起始活性（100％） α :特性因子 t0 :特性時間 Fitted α values 30oC (1) 40oC (3) 50oC (2) 55oC (2) 60oC (1) 升溫後活性衰減機制沒有明顯改變

46 C23Onap(SH1)半衰期隨溫度的變化關係圖
活性半衰期時間 t1/2(T)=t0(ln2)-α Fitted t1/2 values (h) 30oC (9) 40oC (2) 50oC (5) 55oC (5) 60oC (2) 半衰期衰減t1/2(T)=A exp(-T/T0),特性溫度T0=10.7(5)oC

47 活性衰減可能原因 加熱過程使酵素之二價鐵離子氧化 加熱使酵素活性鍵結改變 加熱改變酵素次單位體組態 產生三價鐵離子 ---- 催化作用降低
鐵離子與胺基酸的配位鍵被打斷 鐵離子離開 加熱改變酵素次單位體組態 酵素結構組態被破壞或次單位體大小改變

48 中子散射強度對動量變化關係 5oC  50oC 無明顯變化 55oC 開始變化 60oC  75oC 顯著變化 75oC  83oC
變化趨緩 83oC  5oC Thermal treatment: 5oC  83oC  5oC Å -1 受熱後酵素大小呈現不可逆性變大，轉折溫度為55oC

49 SH1和NCIB9816-4分子的長軸直徑隨溫度變化圖
Native size SH (4)Å NCIB (4)Å After heat cycle SH (5) Å NCIB (5) Å SH1膨脹成~2.7倍, NCIB9816-4膨脹成~2.3倍 次單位體間分離？ 次單位體體積擴張？

50 次單位體間相互分離示意圖 170 Å 95 Å 265 Å 入射中子波長λ= 6 Å, 可解析出各分離的次單位體 與觀察不符

51 次單位體體積擴張示意圖 265 Å 95 Å 入射中子波長λ= 6 Å, 觀測到分子整體 較符合觀察

52 中子散射暑期學校 7月23、24日 國外講員: 1人 ANSTO Dr. M. James 國內講員: 6人 報名人數統計 研究人員 ２６人
研究人員　　　２６人 學　　生　　　７９人 報名人數合計１０５人

53 用戶訪問團 組研究組群 主旨：認識ANSTO 儀器功能，建立合作對口 (不限物理研究群) 第 一梯次
日期：11月28~29日在ANSTO及雪梨大學(SU) 31日在澳洲國立大學(ANU) (物理、 化學、化工 、地科、生科共12人) 第二梯次 (規劃中) 組研究組群 主旨：推動中子散射實驗應用研究 (不限物理研究群) 現況：規劃中

54 李志浩教授 chlee@ess.nthu.edu.tw
歡迎使用 國科會為大家提供的 中子散射實驗設施 聯繫 中央大學中子束應用研究中心 李文献 清華大學原科中心 李志浩教授 國家同步輻射研究中心 梁耕三主任