透射電子顯微鏡基本原理與應(yīng)用2013課件電子衍射

WhatisWhatcanwelearnfromit?Whydoweseeit?Whatdeterminesthescale?WhatdeterminesthedistancesCrystallineoramorphousOrientationoftheA:[120],B:[??單位向量a,b,c表示?？鄏＝ua+vb+wc,則此點(diǎn)陣點(diǎn)的 平面數(shù)截距的倒數(shù)；米氏符號(hào)為(hkl)的面網(wǎng)在晶軸平面上的截距為a/h,b/k,c/l,其分?jǐn)?shù)截距晶體的每個(gè)晶面都和一組平面點(diǎn)陣平行，可用hl)作為與該平面點(diǎn)陣平行的晶面的指標(biāo)。但是，面網(wǎng)符號(hào)與晶面的米氏符號(hào)是有差別的，晶面的米氏符號(hào)中的指數(shù)總是化簡為最簡單的整數(shù)，相互平行的晶面的米氏符號(hào)中的指數(shù)總是相同的，它只有取向的意義，而面網(wǎng)nhnknlnhnknl -(hhhkk(hkhk)3al(hkhk3al)(hkhk3al3d 2dsinθ=n2dsinθ=Sinθ=λ/2d0.00370nm0.00197 O倒易點(diǎn)陣倒易點(diǎn)陣倒易點(diǎn)陣是厄瓦爾德(EwaldPP)在1913 c* ghklha*kb*lcghkl1/a*//a,b*//b,c*//c,a*1,b*1,c* 22dsinθ=nsind O*G2OO*sin21sindEwaldIIhkljFhklFjexp2i(hxjkyjlzj因?yàn)殡娮硬ㄩL很?。ㄈ?00kV時(shí)為0.0037nm），Ewald球半徑1/桿 1x1 D11111在偏離布拉格角±Δθmax范圍內(nèi)，倒易桿都(hkl(hkl(hklhu+kv+lw=HH1u+K1v+L1w=0H2u+K2v+L2w=u:v:wH1K1L1H1K1H2K2L2H2K2u:v:3113113-113-1133-11-44-11 2dsin=tan2=sin2sind區(qū)成象區(qū) 立方ZrO2,a-[111b-[011c-[001],dIn(C)theringofsixdouble-diffractionspotssurroundstheAl2O3reflectionwhilein(D)thedoublediffractionspotssurroundtheFe2O3reflection.forthinforthinfilms,thediffractionspotswillalwaysbethosearrangedaroundthediffractionspotfromthelower CBEDCBED R12：R22：…：Rn利用已知晶體（點(diǎn)陣常數(shù)a已知）多晶衍射花樣d= 為了求準(zhǔn)確的d6363d111=HexagonalR1=3.68/4=0.92hkd1=0.482/0.92=05210R2=6.90/4=1.72500d2=10R3=7.80/4=1.9510d(nm)d(nm)hk0.191100.162110.09821？？？01hhkk(hkhk)3alcos (hkhk )(hkhk 3a2/4c2=0.29219,cos(102V1-10)=0.5/(2.16876×1)0.5=102d(A)hk2.8143102.6033002.4759101.9111101.6247111.4771101.4072201.378211hhk10001010111110201121 11-1000-1-01-3-10-2-2-2- 2236223622(02-22(20-22(-4-22(01-(-22(-1-310300210210110Φ=601201111201000 體心立方，孿生面一般為{112}，孿生方向?yàn)?80轉(zhuǎn)180ht2p(hpkqlr)hkt2q(hpkqlr)klt2r(hpkqlr)lht2npkt2nqlt2nr當(dāng)hp+kq+lr=3n±1（n為整數(shù)）(pqr)=(111),(hkl)=(311);hp+kq+lr=5,ht1p(hpkqlr)hkt1q(hpkqlr)klt1r(hpkqlr)lhtnpktnqltnr孿晶的(hkl)倒易陣點(diǎn)ht=-hkt=-klt=