Influence of complex impurity centres on radiation damage in wide-gap metal oxides

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:374

Article

Lushchik, A.¹  Lushchik, Ch.¹  Popov, A. I.²  Schwartz, K.³  Shablonin, E.¹  Vasil'chenko, E.¹ 

[1] Univ Tartu, Inst Phys, Ravila 14c, EE-50411 Tartu, Estonia

[2] Univ Latvia, Inst Solid State Phys, Kengaraga 8, LV-1063 Riga, Latvia

[3] GSI Helmholtzzentrum Schwerionenforsch GSI, Planckstr 1, D-64291 Darmstadt, Germany

关键词: Radiation defects;    Non-impact mechanisms;    Luminescence;    Impurity centres;    Metal oxides;   

DOI  :  10.1016/j.nimb.2015.07.004

来源: Elsevier

【 摘 要 】

Different mechanisms of radiation damage of wide-gap metal oxides as well as a dual influence of impurity ions on the efficiency of radiation damage have been considered on the example of binary ionic MgO and complex ionic-covalent Lu3Al5O12 single crystals. Particular emphasis has been placed on irradiation with GeV heavy ions (Au-197, Bi-209, U-238, fluence of 10(12) ions/cm(2)) providing extremely high density of electronic excitations within ion tracks. Besides knock-out mechanism for Frenkel pair formation, the additional mechanism through the collapse of mobile discrete breathers at certain lattice places (e.g., complex impurity centres) leads to the creation of complex defects that involve a large number of host atoms. The experimental manifestations of the radiation creation of intrinsic and impurity antisite defects (Lu vertical bar(Al) or Ce vertical bar(Al) - a heavy ion in a wrong cation site) have been detected in LuAG and LuAG:Ce3+ single crystals. Light doping of LuAG causes a small enhancement of radiation resistance, while pair impurity centres (for instance, Ce vertical bar(Lu)-Ce vertical bar(Al) or Cr3+-Cr3+ in MgO) are formed with a rise of impurity concentration. These complex impurity centres as well as radiation-induced intrinsic antisite defects (Lu vertical bar(Al) strongly interacting with Lu in a regular site) tentatively serve as the places for breathers collapse, thus decreasing the material resistance against dense irradiation. (C) 2015 EURATOM. Published by Elsevier B.V. All rights reserved.

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