Phase‐dependent radiation‐resistant behavior of BaTiO₃: An in situ X‐ray diffraction study

Abstract

The radiation-resistant response of BaTiO 3 in the tetragonal and rhombohedral phases on exposure to 100 MeV Ag 7+ ion irradiation was investigated by in situ X-ray diffraction (XRD) at room temperature (300 K) and low temperature (25 K), respectively. This study revealed that the BaTiO 3 in rhombohedral phase retained crystallinity up to an ion fluence of 1910 14 ions/cm 2 , whereas tetragonal phase amorphized at much lower fluence viz. 1910 13 ions/cm 2 . The in situ XRD along with Raman spectroscopy studies revealed that BaTiO 3 in rhombohedral phase is more radiation resistant than that of tetragonal phase. The density functional theory (DFT) calculations confirmed higher bond strength of rhombohedral phase as compared to tetragonal phase, which supported the experimental result of higher radiation stability of rhombohedral phase. The theoretical predictions on high-temperature phase will be of relevance to the nuclear waste applications. orthorhombic (Amm2)?rhombohedral (R3m), in between 400 and 160 K. The high-temperature cubic phase is paraelectric and all the remaining phases are ferroelectric. These structural phase changes are originated due to internal distortions induced stretching of paraelectric cubic lattice along different crystallographic directions, along an edge (<001> in tetragonal), along a face diagonal (<011> in orthorhombic), and along a body diagonal (<111> in rhombohedral). 5,6 On exposure to the energetic heavy ion, properties of the materials are altered by introducing defects, changing structures including amorphization or loss of crystallinity. This type of ion irradiation offers exclusive way of creating extreme surroundings like in nuclear environment, and therefore, the ion irradiation studies of the ABO 3 structures in different phases are of interest because perovskite titanates have potential application for immobilization of fission products and actinides from nuclear waste.

A La and Nb co-doped BaTiO3 film with positive-temperature-coefficient of resistance for thermal protection of batteries

“…1a) show that the tetragonal BaTiO 3 phase (space group P 4 mm ) has been prepared throughout with no impurity phases detected after La and Nb doping. 44 The shift in the 101/110 reflection positions indicates that the La and Nb doping changes the lattice parameters of BaTiO 3 . The undoped and doped BaTiO 3 samples exhibit a tetragonal structure, as clearly seen by the split of, for example, the 101/110 and 200/002 reflections as shown in Fig.…”

Structural Instability in Electrically Stressed, Oxygen Deficient BaTiO3 Nanocrystals

“…The entire nanocrystal also gets rounded after 360 s illumination of the e‐beam, showing that the amorphized area is larger than the e‐beam illuminated area. Amorphization of BaTiO 3 and other types of perovskite oxides has been observed when exposed to energetic ion irradiation typically on the order of MeV scale, [ 17 ] but the effect of applied electric fields on the structural stability of BaTiO 3 nanocrystals towards amorphization has not been noted before and suggests that the defects generated during electrical stressing can also influence the oxide's structural stability.…”