Real-Time Absorption Spectrum Measurements of Deformation-Induced Point Defects in Single Crystal MgO
-
摘要: 为研究冲击塑性变形产生的缺陷对MgO单晶透明性的影响，采用40通道(波长)纳秒时间分辨高温计和冲击波原位光源技术，对在一维应变冲击加载下MgO单晶的透射谱进行了实验测量。冲击波加载方向垂直于样品(100)晶面，测谱范围为400~800 nm，得到了2个压力点(约50 GPa和约70 GPa)的吸收系数随波长的变化曲线，从实测曲线发现了6个明显的特征吸收峰，其中心波长分别为410、460、490、520、580和660 nm。通过对比分析，确定出410、460、490和580 nm处的吸收峰为F聚心吸收，520 nm处的吸收峰为V-心吸收，而660 nm处的吸收峰则可能为与填隙原子相关的吸收。这是在冲击压缩条件下，首次实时观测到的MgO单晶样品冲击塑性变形产生的点缺陷色心吸收现象。Abstract: The purpose of this study is to investigate the effects of deformation-induced defects on optical transparency of MgO single crystal under shock loading.With the nanosecond-time-resolved 40-wavelength radiation pyrometer and shock-compressed in situ light source techniques, transmission spectrums of single crystal MgO shocked along 〈100〉 direction on two-stage gus gun were measured. Spectrums of the measurements ranged from 400 to 800 nm.Curves of absorption coefficients versus wavelengths under ≈50 GPa and ≈70 GPa were obtained.Color center absorption peaks (410, 460, 490, 580 nm assigned to aggregate F type centers; 520 nm to V- center; 660 nm probably to absorption related with interstitial atom) indicate point defects created during shock plastic deformation process.It is for the first time that color centers of point defects were observed in real time.
-
Key words:
- MgO single crystal /
- shock plasticity /
- color center absorption /
- point defect
-
图 1 〈100〉 MgO单晶在常温常压下的吸收谱
Figure 1. Absorption spectrum of 〈100〉 MgO at ambient condition
图 3 〈100〉 MgO单晶典型的辐亮度历史和表观速度剖面(p≈70 GPa, λ≈600 nm)
Figure 3. Typical radiance history and apparent velocity profile (〈100〉 MgO, p≈70 GPa, λ≈600 nm)
图 4 〈100〉 MgO单晶的吸收率随时间和波长的变化
(a) p≈70 GPa (b) p≈50 GPa
Figure 4. Absorbance as a function of time and wavelength (〈100〉 MgO)
图 5 实验测得的吸收谱(〈100〉 MgO单晶)
Figure 5. Absorption spectrums measured in our experiments (〈100〉 MgO)
图 6 扣除吸收本底基线后的特征吸收谱
Figure 6. Characteristic absorption spectrums with baselines subtracted
表 1 相关材料参数
Table 1. Parameters of related materials used in this study
Material ρ0/(g/cm3) C0/(mm/μs) λ γ cV/(J·g-1·K-1) Copper 8.935 3.933 1.500 2.0 - 304SS 7.930 4.580 1.490 2.2 - CHBr3 2.870 1.500 1.380 1.0 0.516 MgO 3.584 6.600 1.370 1.74 - 
下载: 导出CSV
表 2 实验参数
Table 2. Experimental parameters
Shot No. h1/h2 w/
(km/s)CHBr3 MgO pH/(GPa) TH/(K) pH/(GPa) up/(km/s) D/(km/s) 20121212 0.08/2.8 3.84(0.019) 45.7(0.4) 5830 70.3(0.5) 2.077(0.011) 9.446(0.016) 20130108 0.08/3.0 3.04(0.015) 31.7(0.2) 3687 50.4(0.4) 1.601(0.009) 8.793(0.012)
下载: 导出CSV
-
[1] Umemoto K, Wentzcovitch R M, Allen P B. Dissociation of MgSiO3 in the cores of gas giants and terrestrial exoplanets[J]. Science, 2006, 311(5763): 983-986. doi: 10.1126/science.1120865 [2] McWilliams R S, Spaulding D K, Eggert J H, et al. Phase transformations and metallization of magnesium oxide at high pressure and temperature[J]. Science, 2012, 38(6112): 1330-1333. http://www.chemeurope.com/en/publications/495318/report-phase-transformations-and-metallization-of-magnesium-oxide-at-high-pressure-and-temperature.html [3] Stevens G D, Veeser L R, Rigg P A, et al. Suitability of magnesium oxide as a VISAR window[C]//Shock Compression of Condensed Matter-2005. Atlanta: American Institute of Physics, 2006: 1353-1356. [4] Liberman D A. Self-consistent field electronic structure calculations for compressed magnesium oxide[J]. J Phys Chem Solids, 1978, 39(3): 255-257. doi: 10.1016/0022-3697(78)90052-5 [5] Bukowinski M S T. Effect of pressure on bonding in MgO[J]. J Geophys Res: Solid Earth, 1980, 85(B1): 285-292. doi: 10.1029/JB085iB01p00285 [6] Chang K J, Cohen M L. High-pressure behavior of MgO: Structural and electronic properties[J]. Phys Rev B, 1984, 30(8): 4774-4781. doi: 10.1103/PhysRevB.30.4774 [7] 房勇, 杨改蓉, 何林, 等.第一性原理计算分析冲击压缩下MgO电导率突降起因[J].西南大学学报(自然科学版), 2009, 31(9): 93-96. http://www.cqvip.com/QK/95549A/20099/31579918.htmlFang Y, Yang G R, He L, et al. Analysis of the causes for abrupt drop of electronic conductivity of MgO under high pressure using first principle calculation[J]. Journal of Southwest University(Natural Science Edition), 2009, 31(9): 93-96. (in Chinese) http://www.cqvip.com/QK/95549A/20099/31579918.html [8] Bukowinski M S T, Hauser J. Pressure induced metallization of SrO and BaO: Theoretical estimate of transtion pressures[J]. Geophys Res Lett, 1980, 7(9): 689-692. doi: 10.1029/GL007i009p00689 [9] Gaffney E S, Ahrens T J. Optical absorption spectra of ruby and periclase at high shock pressures[J]. J Geophyis Res, 1973, 78(26): 5942-5953. doi: 10.1029/JB078i026p05942 [10] Schmitt D R, Ahrens T J. Emission spectra of shock compressed solids[C]//Asay J R, Graham R A, Struab G K. Shock Waves in Condensed Matter 1983. Amsterdam: Elsevier Science Publishers B V, 1984: 313-316. [11] Schmitt D R, Svendsen B, Ahrens T J. Shock induced radiation from minerals[C]//Gupta Y M. Shock Waves in Condensed Matter-1985. New York and London: Plenum Press, 1986: 261-265. [12] Svendsen B, Ahrens T J. Shock-induced temperatures of MgO[J]. Geophys J Int, 1987, 91(3): 667-691. doi: 10.1111/j.1365-246X.1987.tb01664.x [13] Gager W B, Klein M J, Jones W H. The generation of vacancies in MgO single crystals by explosive shock[J]. Appl Phys Lett, 1964, 5(7): 131-132. doi: 10.1063/1.1754084 [14] Wang Q S, Holzwarth N A W. Electronic structure of vacancy defects in MgO crystals[J]. Phys Rev B, 1990, 41(5): 3211-3225. doi: 10.1103/PhysRevB.41.3211 [15] Gibson A, Haydock R, Lapemina J P. Stability of vacancy defects in MgO: The role of charge neutrality[J]. Phys Rev B, 1994, 50(4): 2582-2592. doi: 10.1103/PhysRevB.50.2582 [16] Meyers M A, Chawla K K. Mechanical Behavior of Materials[M]. 2nd ed. New York: Cambridge University Press, 2009: 259. [17] Klein M J, Gager W B. Generation of vacancies in MgO by deformation[J]. J Appl Phys, 1966, 37(11): 4112-4116. doi: 10.1063/1.1707984 [18] Li J, Zhou X M, Li J B. A time-resolved single-pass technique for measuring optical absorption coefficients of window materials under 100 GPa shock pressures[J]. Rev Sci Instrum, 2008, 79(12): 123107. doi: 10.1063/1.3046279 [19] Goto T, Ahrens T J, Rossman G R, et al. Absorption spectrum of shock-compressed Fe2+-bearing MgO and the radiative conductivity of the lower mantle[J]. Phys Earth Planet Inter, 1980, 22(3/4): 277-288. [20] McQueen R G, Hopson J W, Fritz J N. Optical technique for determining rarefaction wave velocities at very high pressures[J]. Rev Sci Instrum, 1982, 53(2): 245-250. doi: 10.1063/1.1136937 [21] Gogulya M F. Temperatures of Shock Compression of Condensed Matter[M]. Moscow: MIFI, 1988: 3-10. [22] Weng J D, Tan H, Wang X, et al. Optical-fiber interferometer for velocity measurements with picosecond resolution[J]. Appl Phys Lett, 2006, 89(11): 111101. doi: 10.1063/1.2335948 [23] 操秀霞, 卢铁城, 周显明.冲击压缩下蓝宝石单晶散射消光的理论计算[J].原子与分子物理学报, 2011, 28(3): 485-493. http://www.cqvip.com/QK/91990X/201103/38270715.htmlCao X X, Lu T C, Zhou X M. Optical scattering extinction in shocked sapphire by theoretical calculation[J]. Journal of Atomic and Molecular Physics, 2011, 28(3): 485-493. (in Chinese) http://www.cqvip.com/QK/91990X/201103/38270715.html [24] Monge M A, Popov A I, Ballesteros C, et al. Formation of anion-vacancy clusters and nanocavities in thermochemically reduced MgO single crystals[J]. Phys Rev B, 2000, 62(14): 9299-9304. doi: 10.1103/PhysRevB.62.9299 [25] Gonzalez R, Vergara I, CaceresD, et al. Role of hydrogen and lithium impurities in radiation damage in neutron-irradiated MgO single crystals[J]. Phys Rev B, 2002, 65(22): 224108. doi: 10.1103/PhysRevB.65.224108 [26] Caceres D, Vergara I, Gonzalez R, et al. Effect of neutron irradiation on hardening in MgO Crystals[J]. Phys Rev B, 2002, 66(2): 024111. doi: 10.1103/PhysRevB.66.024111 [27] Kvatchadze V, Kalabegishvili T, Vylet V, et al. Ceramic MgO: LiF: promising material for selective detector[J]. Radiat Effect Defect Solid, 2006, 151(5): 305-311. doi: 10.1080/10420150600703767 [28] Henderson B. Anion vacancy centers in alkaline earth oxides[J]. Critic Revn Solid State Mater Sci, 1980, 9(1): 1-60. doi: 10.1080/10408438008243569 [29] Kappers L A, Kroes R L, Hensley E B. F+ and F' centers in magnesium oxide[J]. Phys Rev B, 1970, 1(10): 4151-4157. doi: 10.1103/PhysRevB.1.4151 [30] Ueda A, Mu R, Tung Y S, et al. Optically measured diffusion constants of oxygen vacancies in MgO[J]. J Phys: Conden Matt, 2001, 13(23): 5535-5544. doi: 10.1088/0953-8984/13/23/313 [31] Turner T J, Murphy C, Schultheiss T. A study of the effect of deformation on optical absorption of MgO single crystals[J]. Phys Stat Solid(b), 1973, 58(2): 843-857. doi: 10.1002/pssb.2220580247 [32] Underhill P R, Gallon T E. The surface defect peak in the electron energy loss spectrum of MgO(100)[J]. Solid State Commun, 1982, 43(1): 9-11. http://www.sciencedirect.com/science/article/pii/0038109882911437 [33] 刘健, 阮永丰, 马鹏飞, 等.中子辐照MgO晶体的损伤和恢复[J].人工晶体学报, 2005, 34(3): 496-499. http://d.wanfangdata.com.cn/Periodical/rgjtxb98200503025Liu J, Ruan Y F, Ma P F, et al. Radiation damage and recovery of neutron irradiated MgO crystal[J]. Journal of Synthetic Crystals, 2005, 34(3): 496-499. (in Chinese) http://d.wanfangdata.com.cn/Periodical/rgjtxb98200503025 -
下载:
点击查看大图
图(6) / 表(2)
计量
- 文章访问数: 6854
- HTML全文浏览量: 2127
- PDF下载量: 247
