Structure of 3 at.% and 9 at.% Si-doped HfO2 from combined refinement of X-ray and neutron diffraction patterns

JOURNAL OF ALLOYS AND COMPOUNDS

卷:646

Article

Zhao, Lili^1,2  Hou, Dong¹  Usher, Tedi-Marie¹  Iamsasri, Thanakorn¹  Fancher, Chris M.¹  Forrester, Jennifer S.¹  Nishida, Toshikazu³  Moghaddam, Saeed⁴  Jones, Jacob L.¹ 

[1] N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA

[2] NW Univ Xian, Sch Informat Sci & Technol, Xian 710127, Peoples R China

[3] Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA

[4] Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA

关键词: Crystal structure;    Rietveld refinement;    X-ray diffraction;    Neutron diffraction;   

DOI  :  10.1016/j.jallcom.2015.06.084

来源: Elsevier

【 摘 要 】

The crystal structure of 3 at.% and 9 at.% Si-doped HfO2 powder was determined through refinements using X-ray and neutron diffraction patterns. The lattice parameters, atomic positions, dopant occupancy, and the second phase fraction were determined with high precision using a combined full pattern fitting via the Rietveld method. The results show that both 3 at.% and 9 at.% Si-doped HfO2 powder exhibit the monoclinic crystal structure with P 1 2(1)/c 1 space group. Through the combined refinement, the crystal structure parameters, especially for the positions and occupancies of the lighter atoms, were more precisely determined compared to independent X-ray diffraction refinement. Although the ionic radius of Si4+ is smaller than Hf4+, with increasing Si occupancy, the unit cell volume slightly increases; possible mechanisms for this effect are discussed. Moreover, the refined results provide evidence of the existence of a non-equilibrium phase of HfxSi1-xO2. The second phase (SiO2) fraction is determined as 0.17 at.% for 3 at.% Si-doped HfO2 powders and 1.7 at.% for 9 at.% Si-doped HfO2 powders. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

Free