Effects of heat treatment on the phase transitions in BaTiO₃fine particles

Phase transformation of BaTiO3 nanoparticles synthesized by RF-plasma CVD

“…Li et al suggested that agglomeration of BaTiO 3 nanoparticles promotes the stability of the tetragonal phase [9]. As a result, various critical sizes of phase transformation in the range from 17 to 190 nm have been reported [1,2,5,[9][10][11][12][13][14][15]. Table 1 summarizes the critical sizes of phase transformation reported by other researchers.…”

Application of calorimetry and thermodynamics to critical problems in materials science

“…The high temperature para-electric phase is sustained below the phase transition temperature down to liquid helium temperature, if the particle size is smaller than the critical size of about several nm. The fine particles of BaTiO 3 are aggregated and enlarged by heating, which leads to the ordinary properties of the crystal as shown in figure 13 [50]; the heat capacity anomaly due to the phase transition increases with increasing the heat treatment temperature. The composite structure of the particle is confirmed by means of diffraction using synchrotron radiation high-energy X-ray [51]; according to shell model, the thickness of the surface shell of cubic structure was estimated to be about 8 nm, which was constant irrespective of particle size.…”

“…Recent . Plot of heat capacity against temperature to show the anomaly due to the orthorhombic-tetragonal phase transition in BaTiO 3 particles after various heat treatments [50]. The a refers to bulk, b at T = 1273 K, c at 1073 K, d at 1023 K, e at 873 K. studies by neutron and X-ray diffractometry have shown that a relaxor is in a heterostructure composed of two different phases, ferroelectric nano-regions (abbreviated as FNR) or ferroelectric polar nano-regions (abbreviated as PNR) (space group R3m) formed in para-electric matrix (Pm3m).…”

Fabrication of well-dispersed barium titanate nanoparticles by the electrospray of a colloidal solution

“…[9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] However, the critical sizes reported so far have varied widely, from 10 to 190 nm. These discrepancies seem to originate in the differences of powder properties such as defects, 11 impurities, 25 stress, 24 surface energy, 18 and agglomeration.…”