National Central University ANSTO 95 1031 WenHsien Li

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 whli@phy. ncu. edu. tw

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

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

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

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 me. V With RSET : E ~ 1 to 100 e. V (optional) A spin-echo cold neutron triple-axis spectrometer

SIKA A cold-neutron triple-axis spectrometer at ANSTO 冷三軸 2010 spring 熱三軸 2007 Sept. Reactor face SIKA 計畫時程 (2006, 09修訂) an p i a T (概念設計) ( 程設計) (採購) (組裝) (測試) 2006 2007 2008 2009 le ip Tr SIKA ld o C xis A 1 Å = 82 me. V 2 Å = 20. 5 me. V 4 Å = 5 me. V 6. 2 Å = 2. 3 me. V

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

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

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

Stabilization of crystal structure Li 0. 99(Mn 0. 976 Co 0. 024)2 O 4. 036 λ = 1. 5402 Å 15'-20' -7' No structural distortion was observed bet. 9 & 300 K A 2. 5% Co-doping stabilizes the crystalline structure.

Two-step short-range Mn spin ordering Magnetic unit cell I 1. 4 K - I 80 K Two separate magnetic components Ordering temperatures for the two components: at 90 K & 50 K Separate ordering of Mn 3+ and Mn 4+.

Cluster structure of Mn 3+ and Mn 4+ PRL 81, 4660 (1998) Mn 3+ (electron-rich region) 被 Mn 4+ (hole-rich region) 所環繞形成叢集的 型態。 並非Mn 4+和Mn 3+交替排列。

Ferromagnetic clusters and antiferromagnetic coupling in lightly Cr-doped (Bi/Ca)Mn. O 3 whli@phy. ncu. edu. tw

Two polycrystalline samples Bix. Ca 1 -x. Mn 0. 95 Cr 0. 05 O 3 x=0. 4 and 0. 5

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

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.

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.

BCMCO Transport behavior Temperature dependence of 1/T 1/4 of electric resistivity of Bi 0. 4 Ca 0. 6 Mn 0. 95 Cr 0. 05 O 3. This figure plots follow the Mott’s variable-range hoping (VRH) of the charge carriers. ρVHR= ρ0 exp(T 0/T)1/4. The fitting parameter T 0(0 T)= 49 K, ρ0=7. 8(7)× 10 -7 Ω-cm. An anomaly was found at around 280 K.

BCMCO Magnetic susceptibility μest= 4. 43μB

Neutron magnetic diffraction BCMCO Magnetic diffraction pattern + model fit

BCMCO Magnetic Structure 90° c c 90° a 45° Mn 3+ b a 45° b Mn 4+ Mn 3+: Mn 4+=10: 6 <μ> = 1. 78(1) μB Bi 0. 4 Ca 0. 6 Mn 0. 95 Cr 0. 05 O 3

BCMCO Magnetic Structure c Bi 0. 5 Ca 0. 5 Mn 0. 95 Cr 0. 05 O 3 <μ> = 1. 31(4) μB b a

BCMCO Order parameters Bi 0. 5 Ca 0. 5 Mn 0. 95 Cr 0. 05 O 3 TN=80 K Bi 0. 5 Ca 0. 5 Mn 0. 95 Cr 0. 05 O 3 TN=90 K

Basic physical properties of RBa 2 Cu 3 O 6+x(R 123) R=稀土元素 R + 2(Ba. O) + 2(Cu. O 2) + Cu. Ox 導電性及磁性均受控於x 隔離層 Cu(2) 超導層 稀土層 RBa 2 Cu 3 O 7: 98 K超導體 (除R=Pr) R反鐵磁有序(TN<1 K) R 超導層 O(2) 隔離層 O(1) 電洞庫層 Ba 但Pr. Ba 2 Cu 3 O 7: TC=0 K (無超導電性) TN(Pr)=17 K Cu(1) TN(Cu)=270 K O(4)

高解析度中子繞射譜圖 Counts / min 2000 1800 Pr. Ba 2 Cu 3 O 6+y o = 1. 5402 A l 1600 15'-20'-7' 1400 1200 1000 800 600 400 200 1005 1004 1003 1002 0 20 40 60 80 100 Scattering angle 2 q 120 140 160

Crystal structure & nuclear density contours Pr. Ba 2 Cu 3 O 6. 338 Cu(2) Pr 76. 49°(7) 2. 4882(12) Å 103. 51°(7) O(2) c b a 2. 7991(9) Å c Center at (1/2 0) Center at (1/2 1/2) O(1) a Ba Cu(1) O(4)

Nuclear density contours Pr. Ba 2 Cu 3 O 6. 338 Center (1/2, 0) Center (1/2, 0. 19) b a (1/ Center 1 2, /2, 0. 352) Center 1 1 2, /2) (1/

奈米物性實驗室 Polymer intercalated Fe. OCl

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

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

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

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

Subjects 主題 1. 溫度對酵素活性的影響(熱穩定性) 2. 溫度對酵素結構組態的效應 具 1. Biological analysis 2. Activation analysis 3. Small angle neutron scattering 系統 1. C 23 Onap(SH 1) --- 台灣 2. C 23 Onap(NCIB 9816 -4) --- 美國

C 23 Otol(mt-2)的次單位體結構圖 Lc Lb La= 0. 8 Lc Lb = 0. 6 Lc Kita et al. Structure 7, 25(1999)

C 23 Otol(mt-2)的分子組態與尺度 66 Å b 94 Å ~ 94 Å (單晶) a c da : db : dc = 48 Å : 66 Å : 94 Å = 0. 5 : 0. 7 : 1 Kita et al. structure 7, 25(1999)

C 23 Onap(SH 1)半衰期隨溫度的變化關係 圖 活性半衰期時間 t 1/2(T)=t 0(ln 2)-α Fitted t 1/2 values (h) 30 o. C 12. 73(9) 40 o. C 6. 78(2) 50 o. C 1. 24(5) 55 o. C 0. 46(5) 60 o. C 0. 24(2) 半衰期衰減t 1/2(T)=A exp(-T/T 0), 特性溫度T 0=10. 7(5)o. C

SH 1和NCIB 9816 -4分子的長軸直徑隨溫度變化圖 Native size SH 1 95(4)Å NCIB 95(4)Å After heat cycle SH 1 253(5) Å NCIB 218(5) Å SH 1膨脹成~2. 7倍, NCIB 9816 -4膨脹成~2. 3倍 次單位體間分離？ 次單位體體積擴張？