Defects and solarization in YAG transparent ceramics
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摘要
Transparent ceramics are emerging as future materials for lasers, scintillation, and illumination. In this paper, an interesting and surprising phenomenon in YAG transparent ceramics is reported. UV light leads to significant changes in the microstructure of open volume defects and nano clusters as well as in the optical properties. Lightinduced lattice relaxation is suggested as the mechanism behind this intriguing behavior. The complex F-type color center with broad absorption bands is caused by the aliovalent sintering additives(Ca~(2+)∕Mg~(2+)) and Fe ion impurities. Two individual peaks in the thermoluminescence spectra illustrate both shallow and deep level traps.From positron annihilation lifetime data, vacancy clusters and nanovoids are detected and characterized, although these free-volume defects could not be observed by high-resolution transmission electron microscopy. The solarization induced by UV irradiation is associated with a change in the structure and size of defect clusters due to lattice relaxation. Therefore, this work shows how UV irradiation leads not only to a change in the charge state of defects, but also to a permanent change in defect structure and size. It significantly affects the optical properties of YAG ceramics and their performance in lasers and other optical applications. These results are crucial for advancing transparent ceramics technology.
Transparent ceramics are emerging as future materials for lasers, scintillation, and illumination. In this paper, an interesting and surprising phenomenon in YAG transparent ceramics is reported. UV light leads to significant changes in the microstructure of open volume defects and nano clusters as well as in the optical properties. Lightinduced lattice relaxation is suggested as the mechanism behind this intriguing behavior. The complex F-type color center with broad absorption bands is caused by the aliovalent sintering additives(Ca~(2+)∕Mg~(2+)) and Fe ion impurities. Two individual peaks in the thermoluminescence spectra illustrate both shallow and deep level traps.From positron annihilation lifetime data, vacancy clusters and nanovoids are detected and characterized, although these free-volume defects could not be observed by high-resolution transmission electron microscopy. The solarization induced by UV irradiation is associated with a change in the structure and size of defect clusters due to lattice relaxation. Therefore, this work shows how UV irradiation leads not only to a change in the charge state of defects, but also to a permanent change in defect structure and size. It significantly affects the optical properties of YAG ceramics and their performance in lasers and other optical applications. These results are crucial for advancing transparent ceramics technology.
Transparent ceramics are emerging as future materials for lasers, scintillation, and illumination. In this paper, an interesting and surprising phenomenon in YAG transparent ceramics is reported. UV light leads to significant changes in the microstructure of open volume defects and nano clusters as well as in the optical properties. Lightinduced lattice relaxation is suggested as the mechanism behind this intriguing behavior. The complex F-type color center with broad absorption bands is caused by the aliovalent sintering additives(Ca~(2+)∕Mg~(2+)) and Fe ion impurities. Two individual peaks in the thermoluminescence spectra illustrate both shallow and deep level traps.From positron annihilation lifetime data, vacancy clusters and nanovoids are detected and characterized, although these free-volume defects could not be observed by high-resolution transmission electron microscopy. The solarization induced by UV irradiation is associated with a change in the structure and size of defect clusters due to lattice relaxation. Therefore, this work shows how UV irradiation leads not only to a change in the charge state of defects, but also to a permanent change in defect structure and size. It significantly affects the optical properties of YAG ceramics and their performance in lasers and other optical applications. These results are crucial for advancing transparent ceramics technology.
引文
1.A.Ikesue and Y.L.Aung,“Ceramic laser materials,”Nat.Photonics 2,721-727(2008).
2.A.Ikesue,T.Kinoshita,K.Kamata,and K.Yoshida,“Fabrication and optical properties of high-performance polycrystalline Nd:YAG ceramics for solid-state lasers,”J.Am.Ceram.Soc.78,1033-1040(1995).
3.H.Furuse,Y.Koike,and R.Yasuhara,“Sapphire/Nd:YAG composite by pulsed electric current bonding for high-average-power lasers,”Opt.Lett.43,3065-3068(2018).
4.S.Bigotta,L.Galecki,A.Katz,J.Bohmler,S.Lemonnier,E.Barraud,A.Leriche,and M.Eichhorn,“Resonantly pumped eye-safe Er3+:YAGSPS-HIP ceramic laser,”Opt.Express 26,3435-3442(2018).
5.A.S.Kaygorodov,V.V.Ivanov,V.R.Khrustov,Y.A.Kotov,A.I.Medvedev,V.V.Osipov,M.G.Ivanov,A.N.Orlov,and A.M.Murzakaev,“Fabrication of Nd:Y2O3transparent ceramics by pulsed compaction and sintering of weakly agglomerated nanopowders,”J.Eur.Ceram.Soc.27,1165-1169(2007).
6.H.Uehara,S.Tokita,J.Kawanaka,D.Konishi,M.Murakami,S.Shimizu,and R.Yasuhara,“Optimization of laser emission at2.8μm by Er:Lu2O3ceramics,”Opt.Express 26,3497-3507(2018).
7.N.Nishiyama,R.Ishikawa,H.Ohfuji,H.Marquardt,A.Kurnosov,T.Taniguchi,B.N.Kim,H.Yoshida,A.Masuno,J.Bednarcik,E.Kulik,Y.Ikuhara,F.Wakai,and T.Irifune,“Transparent polycrystalline cubic silicon nitride,”Sci.Rep.7,44755(2017).
8.C.Ma,J.Zhu,K.Liu,F.Tang,J.Long,Z.Wen,R.Ma,X.Yuan,W.Guo,J.Li,and Y.Cao,“Longitudinally diode-pumped planar waveguide YAG/Yb:LuAG/YAG ceramic laser at 1030.7 nm,”Opt.Lett.41,3317-3319(2016).
9.B.Villars,E.S.Hill,and C.G.Durfee,“Design and development of a high-power LED-pumped Ce:Nd:YAG laser,”Opt.Lett.40,3049-3052(2015).
10.R.Boulesteix,A.Maitre,J.F.Baumard,Y.Rabinovitch,and F.Reynaud,“Light scattering by pores in transparent Nd:YAG ceramics for lasers:correlations between microstructure and optical properties,”Opt.Express 18,14992-15002(2010).
11.A.Ikesue and K.Yoshida,“Influence of pore volume on laser performance of Nd:YAG ceramics,”J.Mater.Sci.34,1189-1195(1999).
12.K.Hasegawa,T.Ichikawa,S.Mizuno,Y.Takeda,H.Ito,A.Ikesue,T.Motohiro,and M.Yamaga,“Energy transfer efficiency from Cr3+to Nd3+in solar-pumped laser using transparent Nd/Cr:Y3Al5O12ceramics,”Opt.Express 23,A519-A524(2015).
13.H.Yagi,T.Yanagitani,and K.-I.Ueda,“Nd3+:Y3Al5O12laser ceramics:flashlamp pumped laser operation with a UV cut filter,”J.Alloy.Compd.421,195-199(2006).
14.L.Wen,X.D.Sun,Z.Xiu,S.W.Chen,and C.T.Tsai,“Synthesis of nanocrystalline yttria powder and fabrication of transparent YAGceramics,”J.Eur.Ceram.Soc.24,2681-2688(2004).
15.I.Shoji,S.Kurimura,Y.Sato,T.Taira,A.Ikesue,and K.Yoshida,“Optical properties and laser characteristics of highly Nd3+-doped Y3Al5O12ceramics,”Appl.Phys.Lett.77,939-941(2000).
16.M.Bass and A.E.Paladino,“Color centers in yttrium gallium garnet and yttrium aluminum garnet,”J.Appl.Phys.38,2706-2707(1967).
17.K.Mori,“Transient colour centres caused by UV light irradiation in yttrium aluminum garnet crystals,”Phys.Status Solidi A 42,375-384(1977).
18.A.Patel,M.Levy,R.Grimes,R.Gaume,R.Feigelson,K.McClellan,and C.Stanek,“Mechanisms of nonstoichiometry in Y3Al5O12,”Appl.Phys.Lett.93,191902(2008).
19.M.M.Kuklja and R.Pandey,“Atomistic modeling of native point defects in yttrium aluminum garnet crystals,”J.Am.Ceram.Soc.82,2881-2886(1999).
20.S.Rotman,R.Tandon,and H.Tuller,“Defect-property correlations in garnet crystals:the electrical conductivity and defect structure of luminescent cerium-doped yttrium aluminum garnet,”J.Appl.Phys.57,1951-1955(1985).
21.S.Rotman,H.Tuller,and C.Warde,“Defect-property correlations in garnet crystals.VI.The electrical conductivity,defect structure,and optical properties of luminescent calcium and cerium-doped yttrium aluminum garnet,”J.Appl.Phys.71,1209-1214(1992).
22.C.Brecher,G.C.Wei,and W.H.Rhodes,“Point defects in optical ceramics:high-temperature absorption processes in lanthanastrengthened yttria,”J.Am.Ceram.Soc.73,1473-1488(1990).
23.L.Brock,K.Mishra,M.Raukas,W.P.Lapatovich,and G.C.Wei,“Color centers in magnesium doped polycrystalline alumina,”MRSOnline Proc.Library Archive 667,G7(2001).
24.H.Haneda,I.Sakaguchi,N.Ohashi,N.Saito,K.Matsumoto,T.Nakagawa,T.Yanagitani,and H.Yagi,“Evaluation of oxide ion diffusivity in YAG ceramics,”Mater.Sci.Technol.25,1341-1345(2009).
25.E.Zych,C.Brecher,and H.Lingertat,“Depletion of high-energy carriers in YAG optical ceramic materials,”Spectrochim.Acta A 54,1771-1777(1998).
26.S.H.Lee,E.R.Kupp,A.J.Stevenson,J.M.Anderson,G.L.Messing,X.Li,E.C.Dickey,J.Q.Dumm,V.K.Simonaitis‐Castillo,and G.J.Quarles,“Hot isostatic pressing of transparent Nd:YAG ceramics,”J.Am.Ceram.Soc.92,1456-1463(2009).
27.L.Zhang,T.Zhou,F.A.Selim,and H.Chen,“Single CaO accelerated densification and microstructure control of highly transparent YAGceramic,”J.Am.Ceram.Soc.101,703-712(2018).
28.L.Zhang,H.Yang,X.Qiao,T.Zhou,Z.Wang,J.Zhang,D.Tang,D.Shen,and Q.Zhang,“Systematic optimization of spray drying for YAGtransparent ceramics,”J.Eur.Ceram.Soc.35,2391-2401(2015).
29.F.Selim,A.Khamehchi,D.Winarski,and S.Agarwal,“Synthesis and characterization of Ce:YAG nano-phosphors and ceramics,”Opt.Mater.Express 6,3704-3715(2016).
30.J.Ji,L.Boatner,and F.Selim,“Donor characterization in ZnO by thermally stimulated luminescence,”Appl.Phys.Lett.105,041102(2014).
31.P.Husband,I.Barto?ová,V.Slugeň,and F.Selim,“Positron annihilation in transparent ceramics,”J.Phys.Conf.Ser.674,012013(2016).
32.H.Klym,“Study of nanoporous in humidity-sensitive MgAl2O4ceramics with positron annihilation lifetime spectroscopy,”Semicond.Phys.Quantum Electron.Optoelectron.14,109-113(2011).
33.D.Giebel and J.Kansy,“LT10 program for solving basic problems connected with defect detection,”Phys.Procedia 35,122-127(2012).
34.A.J.Stevenson,“The effects of sintering aids on defects,densification,and single crystal conversion of transparent neodymium:YAGceramics,”Ph.D.thesis(The Pennsylvania State University,2010).
35.A.J.Stevenson,X.Li,M.A.Martinez,J.M.Anderson,D.L.Suchy,E.R.Kupp,E.C.Dickey,K.T.Mueller,and G.L.Messing,“Effect of SiO2on densification and microstructure development in Nd:YAG transparent ceramics,”J.Am.Ceram.Soc.94,1380-1387(2011).
36.I.S.Akhmadullin,S.A.Migachev,and S.P.Mironov,“Thermo-and photoinduced defects in Y3Al5O12crystals,”Nucl.Instrum.Meth.B 65,270-274(1992).
37.C.R.Varney,D.T.Mackay,A.Pratt,S.M.Reda,and F.A.Selim,“Energy levels of exciton traps in yttrium aluminum garnet single crystals,”J.Appl.Phys.111,063505(2012).
38.F.A.Selim,C.R.Varney,M.C.Tarun,M.C.Rowe,G.S.Collins,and M.D.McCluskey,“Positron lifetime measurements of hydrogen passivation of cation vacancies in yttrium aluminum oxide garnets,”Phys.Rev.B 88,174102(2013).
39.D.T.Mackay,C.R.Varney,J.Buscher,and F.A.Selim,“Study of exciton dynamics in garnets by low temperature thermo-luminescence,”J.Appl.Phys.112,023522(2012).
40.C.Varney,D.Mackay,S.Reda,and F.Selim,“On the optical properties of undoped and rare-earth-doped yttrium aluminium garnet single crystals,”J.Phys.D 45,218-224(2011).
41.V.Babin,K.Blazek,A.Krasnikov,K.Nejezchleb,M.Nikl,T.Savikhina,and S.Zazubovich,“Luminescence of undoped Lu AGand YAG crystals,”Phys.Status Solidi C 2,97-100(2005).
42.H.Klym,A.Ingram,O.Shpotyuk,I.Hadzaman,V.Solntsev,O.Hotra,and A.I.Popov,“Positron annihilation characterization of free volume in micro-and macro-modified Cu0.4Co0.4Ni0.4Mn1.8O4ceramics,”Low.Temp.Phys.42,601-605(2016).
43.V.Balitska,J.Filipecki,A.Ingram,and O.Shpotyuk,“Defect characterization methodology in sintered functional spinels with PALS technique,”Phys.Status Solidi C 4,1317-1320(2007).
44.O.Shpotyuk,A.Ingram,H.Klym,M.Vakiv,I.Hadzaman,and J.Filipecki,“PAL spectroscopy in application to humidity-sensitive MgAl2O4ceramics,”J.Eur.Ceram.Soc.25,2981-2984(2005).
45.L.G.Jacobsohn,K.Serivalsatit,C.A.Quarles,and J.Ballato,“Investigation of Er-doped Sc2O3transparent ceramics by positron annihilation spectroscopy,”J.Mater.Sci.50,3183-3188(2015).
46.P.J.Schultz and K.G.Lynn,“Interaction of positron beams with surfaces,thin films,and interfaces,”Rev.Mod.Phys.60,701-779(1988).
47.K.Ito,H.Nakanishi,and Y.Ujihira,“Extension of the equation for the annihilation lifetime of ortho-positronium at a cavity larger than 1 nm in radius,”J.Phys.Chem.B 103,4555-4558(1999).
48.X.Feng,“Anti-site defects in YAG and LuAG crystals,”J.Inorg.Mater.25,785-794(2010).
49.Y.He,X.Ma,Z.Gui,and L.Li,“Point defect studies on perovskite structured piezoelectric ceramics using positron annihilation,”Acta Phys.Sinica 47,146-153(1998).
2.A.Ikesue,T.Kinoshita,K.Kamata,and K.Yoshida,“Fabrication and optical properties of high-performance polycrystalline Nd:YAG ceramics for solid-state lasers,”J.Am.Ceram.Soc.78,1033-1040(1995).
3.H.Furuse,Y.Koike,and R.Yasuhara,“Sapphire/Nd:YAG composite by pulsed electric current bonding for high-average-power lasers,”Opt.Lett.43,3065-3068(2018).
4.S.Bigotta,L.Galecki,A.Katz,J.Bohmler,S.Lemonnier,E.Barraud,A.Leriche,and M.Eichhorn,“Resonantly pumped eye-safe Er3+:YAGSPS-HIP ceramic laser,”Opt.Express 26,3435-3442(2018).
5.A.S.Kaygorodov,V.V.Ivanov,V.R.Khrustov,Y.A.Kotov,A.I.Medvedev,V.V.Osipov,M.G.Ivanov,A.N.Orlov,and A.M.Murzakaev,“Fabrication of Nd:Y2O3transparent ceramics by pulsed compaction and sintering of weakly agglomerated nanopowders,”J.Eur.Ceram.Soc.27,1165-1169(2007).
6.H.Uehara,S.Tokita,J.Kawanaka,D.Konishi,M.Murakami,S.Shimizu,and R.Yasuhara,“Optimization of laser emission at2.8μm by Er:Lu2O3ceramics,”Opt.Express 26,3497-3507(2018).
7.N.Nishiyama,R.Ishikawa,H.Ohfuji,H.Marquardt,A.Kurnosov,T.Taniguchi,B.N.Kim,H.Yoshida,A.Masuno,J.Bednarcik,E.Kulik,Y.Ikuhara,F.Wakai,and T.Irifune,“Transparent polycrystalline cubic silicon nitride,”Sci.Rep.7,44755(2017).
8.C.Ma,J.Zhu,K.Liu,F.Tang,J.Long,Z.Wen,R.Ma,X.Yuan,W.Guo,J.Li,and Y.Cao,“Longitudinally diode-pumped planar waveguide YAG/Yb:LuAG/YAG ceramic laser at 1030.7 nm,”Opt.Lett.41,3317-3319(2016).
9.B.Villars,E.S.Hill,and C.G.Durfee,“Design and development of a high-power LED-pumped Ce:Nd:YAG laser,”Opt.Lett.40,3049-3052(2015).
10.R.Boulesteix,A.Maitre,J.F.Baumard,Y.Rabinovitch,and F.Reynaud,“Light scattering by pores in transparent Nd:YAG ceramics for lasers:correlations between microstructure and optical properties,”Opt.Express 18,14992-15002(2010).
11.A.Ikesue and K.Yoshida,“Influence of pore volume on laser performance of Nd:YAG ceramics,”J.Mater.Sci.34,1189-1195(1999).
12.K.Hasegawa,T.Ichikawa,S.Mizuno,Y.Takeda,H.Ito,A.Ikesue,T.Motohiro,and M.Yamaga,“Energy transfer efficiency from Cr3+to Nd3+in solar-pumped laser using transparent Nd/Cr:Y3Al5O12ceramics,”Opt.Express 23,A519-A524(2015).
13.H.Yagi,T.Yanagitani,and K.-I.Ueda,“Nd3+:Y3Al5O12laser ceramics:flashlamp pumped laser operation with a UV cut filter,”J.Alloy.Compd.421,195-199(2006).
14.L.Wen,X.D.Sun,Z.Xiu,S.W.Chen,and C.T.Tsai,“Synthesis of nanocrystalline yttria powder and fabrication of transparent YAGceramics,”J.Eur.Ceram.Soc.24,2681-2688(2004).
15.I.Shoji,S.Kurimura,Y.Sato,T.Taira,A.Ikesue,and K.Yoshida,“Optical properties and laser characteristics of highly Nd3+-doped Y3Al5O12ceramics,”Appl.Phys.Lett.77,939-941(2000).
16.M.Bass and A.E.Paladino,“Color centers in yttrium gallium garnet and yttrium aluminum garnet,”J.Appl.Phys.38,2706-2707(1967).
17.K.Mori,“Transient colour centres caused by UV light irradiation in yttrium aluminum garnet crystals,”Phys.Status Solidi A 42,375-384(1977).
18.A.Patel,M.Levy,R.Grimes,R.Gaume,R.Feigelson,K.McClellan,and C.Stanek,“Mechanisms of nonstoichiometry in Y3Al5O12,”Appl.Phys.Lett.93,191902(2008).
19.M.M.Kuklja and R.Pandey,“Atomistic modeling of native point defects in yttrium aluminum garnet crystals,”J.Am.Ceram.Soc.82,2881-2886(1999).
20.S.Rotman,R.Tandon,and H.Tuller,“Defect-property correlations in garnet crystals:the electrical conductivity and defect structure of luminescent cerium-doped yttrium aluminum garnet,”J.Appl.Phys.57,1951-1955(1985).
21.S.Rotman,H.Tuller,and C.Warde,“Defect-property correlations in garnet crystals.VI.The electrical conductivity,defect structure,and optical properties of luminescent calcium and cerium-doped yttrium aluminum garnet,”J.Appl.Phys.71,1209-1214(1992).
22.C.Brecher,G.C.Wei,and W.H.Rhodes,“Point defects in optical ceramics:high-temperature absorption processes in lanthanastrengthened yttria,”J.Am.Ceram.Soc.73,1473-1488(1990).
23.L.Brock,K.Mishra,M.Raukas,W.P.Lapatovich,and G.C.Wei,“Color centers in magnesium doped polycrystalline alumina,”MRSOnline Proc.Library Archive 667,G7(2001).
24.H.Haneda,I.Sakaguchi,N.Ohashi,N.Saito,K.Matsumoto,T.Nakagawa,T.Yanagitani,and H.Yagi,“Evaluation of oxide ion diffusivity in YAG ceramics,”Mater.Sci.Technol.25,1341-1345(2009).
25.E.Zych,C.Brecher,and H.Lingertat,“Depletion of high-energy carriers in YAG optical ceramic materials,”Spectrochim.Acta A 54,1771-1777(1998).
26.S.H.Lee,E.R.Kupp,A.J.Stevenson,J.M.Anderson,G.L.Messing,X.Li,E.C.Dickey,J.Q.Dumm,V.K.Simonaitis‐Castillo,and G.J.Quarles,“Hot isostatic pressing of transparent Nd:YAG ceramics,”J.Am.Ceram.Soc.92,1456-1463(2009).
27.L.Zhang,T.Zhou,F.A.Selim,and H.Chen,“Single CaO accelerated densification and microstructure control of highly transparent YAGceramic,”J.Am.Ceram.Soc.101,703-712(2018).
28.L.Zhang,H.Yang,X.Qiao,T.Zhou,Z.Wang,J.Zhang,D.Tang,D.Shen,and Q.Zhang,“Systematic optimization of spray drying for YAGtransparent ceramics,”J.Eur.Ceram.Soc.35,2391-2401(2015).
29.F.Selim,A.Khamehchi,D.Winarski,and S.Agarwal,“Synthesis and characterization of Ce:YAG nano-phosphors and ceramics,”Opt.Mater.Express 6,3704-3715(2016).
30.J.Ji,L.Boatner,and F.Selim,“Donor characterization in ZnO by thermally stimulated luminescence,”Appl.Phys.Lett.105,041102(2014).
31.P.Husband,I.Barto?ová,V.Slugeň,and F.Selim,“Positron annihilation in transparent ceramics,”J.Phys.Conf.Ser.674,012013(2016).
32.H.Klym,“Study of nanoporous in humidity-sensitive MgAl2O4ceramics with positron annihilation lifetime spectroscopy,”Semicond.Phys.Quantum Electron.Optoelectron.14,109-113(2011).
33.D.Giebel and J.Kansy,“LT10 program for solving basic problems connected with defect detection,”Phys.Procedia 35,122-127(2012).
34.A.J.Stevenson,“The effects of sintering aids on defects,densification,and single crystal conversion of transparent neodymium:YAGceramics,”Ph.D.thesis(The Pennsylvania State University,2010).
35.A.J.Stevenson,X.Li,M.A.Martinez,J.M.Anderson,D.L.Suchy,E.R.Kupp,E.C.Dickey,K.T.Mueller,and G.L.Messing,“Effect of SiO2on densification and microstructure development in Nd:YAG transparent ceramics,”J.Am.Ceram.Soc.94,1380-1387(2011).
36.I.S.Akhmadullin,S.A.Migachev,and S.P.Mironov,“Thermo-and photoinduced defects in Y3Al5O12crystals,”Nucl.Instrum.Meth.B 65,270-274(1992).
37.C.R.Varney,D.T.Mackay,A.Pratt,S.M.Reda,and F.A.Selim,“Energy levels of exciton traps in yttrium aluminum garnet single crystals,”J.Appl.Phys.111,063505(2012).
38.F.A.Selim,C.R.Varney,M.C.Tarun,M.C.Rowe,G.S.Collins,and M.D.McCluskey,“Positron lifetime measurements of hydrogen passivation of cation vacancies in yttrium aluminum oxide garnets,”Phys.Rev.B 88,174102(2013).
39.D.T.Mackay,C.R.Varney,J.Buscher,and F.A.Selim,“Study of exciton dynamics in garnets by low temperature thermo-luminescence,”J.Appl.Phys.112,023522(2012).
40.C.Varney,D.Mackay,S.Reda,and F.Selim,“On the optical properties of undoped and rare-earth-doped yttrium aluminium garnet single crystals,”J.Phys.D 45,218-224(2011).
41.V.Babin,K.Blazek,A.Krasnikov,K.Nejezchleb,M.Nikl,T.Savikhina,and S.Zazubovich,“Luminescence of undoped Lu AGand YAG crystals,”Phys.Status Solidi C 2,97-100(2005).
42.H.Klym,A.Ingram,O.Shpotyuk,I.Hadzaman,V.Solntsev,O.Hotra,and A.I.Popov,“Positron annihilation characterization of free volume in micro-and macro-modified Cu0.4Co0.4Ni0.4Mn1.8O4ceramics,”Low.Temp.Phys.42,601-605(2016).
43.V.Balitska,J.Filipecki,A.Ingram,and O.Shpotyuk,“Defect characterization methodology in sintered functional spinels with PALS technique,”Phys.Status Solidi C 4,1317-1320(2007).
44.O.Shpotyuk,A.Ingram,H.Klym,M.Vakiv,I.Hadzaman,and J.Filipecki,“PAL spectroscopy in application to humidity-sensitive MgAl2O4ceramics,”J.Eur.Ceram.Soc.25,2981-2984(2005).
45.L.G.Jacobsohn,K.Serivalsatit,C.A.Quarles,and J.Ballato,“Investigation of Er-doped Sc2O3transparent ceramics by positron annihilation spectroscopy,”J.Mater.Sci.50,3183-3188(2015).
46.P.J.Schultz and K.G.Lynn,“Interaction of positron beams with surfaces,thin films,and interfaces,”Rev.Mod.Phys.60,701-779(1988).
47.K.Ito,H.Nakanishi,and Y.Ujihira,“Extension of the equation for the annihilation lifetime of ortho-positronium at a cavity larger than 1 nm in radius,”J.Phys.Chem.B 103,4555-4558(1999).
48.X.Feng,“Anti-site defects in YAG and LuAG crystals,”J.Inorg.Mater.25,785-794(2010).
49.Y.He,X.Ma,Z.Gui,and L.Li,“Point defect studies on perovskite structured piezoelectric ceramics using positron annihilation,”Acta Phys.Sinica 47,146-153(1998).