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Title: Barium titanate nanoparticles: Short-range lattice distortions with long-range cubic order

Journal Article · · Physical Review B
 [1];  [2];  [3];  [4];  [4];  [4];  [4];  [4];  [4];  [5]
  1. Columbia Univ., New York, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States); Columbia Univ., New York, NY (United States)
  3. Pomona College, Claremont, CA (United States)
  4. Harvey Mudd College, Claremont, CA (United States)
  5. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Barium titanate (BTO) nanoparticles (sizes 10 to 500 nm) exhibit a displacement of the Ti atom from the center of the Perovskite unit cell as inferred from synchrotron X-ray diffraction patterns (XRD) analyzed using atomic pair distribution functions (PDFs). Fits to PDFs acquired at temperatures of 20° to 220°C indicate that these Ti displacements (~ 0.1 Å) are comparable to or even greater than those in the bulk material. Moreover, these displacements persist at temperatures well above 120°C where the tetragonal to pseudo-cubic phase transition occurs in the bulk. Tetragonal Raman spectral lines were observed for all sizes of these BTO nanoparticles and confirm a distorted unit cell up to 120°C. Above 120°C, the small BTO nanoparticles (10, 50, 100 nm) continue to display tetragonal Raman lines, though with slowly decreasing amplitudes as the temperature rises. In contrast, the tetragonal Raman lines of large BTO nanoparticles (300, 400, 500 nm) disappear abruptly above 120°C, suggestive of bulk material. Indeed, fits to large-particle X-ray PDFs over the range 20-60 Å reveal a sharp, long-range structural change toward a cubic lattice at 120°C, again consistent with bulk material. This sharp, long-range structural change is absent in the small particles. In fact, laboratory XRD Bragg peak profiles for the small BTO particles appear to be singlets at 20°C, indicating that significant long-range cubic order already exists at room temperature. As temperature rises, this long-range cubic order is gradually reinforced as inferred from long-range fits of the small particle PDFs. By combining information from X-ray PDFs, Raman spectra, and Bragg peak profiles, we conclude that small BTO nanoparticles exhibit both short-range (unit-cell) distortion and long-range (mesoscale) cubic order from 20° to 220°C, while the large nanoparticles behave as bulk material, differing from small particles only by exhibiting long-range tetragonal order below 120°C and a mesoscale structural phase change at 120°C.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE
Grant/Contract Number:
SC0012704; NA0003525; AC02-98CH10886
OSTI ID:
1469784
Alternate ID(s):
OSTI ID: 1464657; OSTI ID: 1472263
Report Number(s):
BNL-209026-2018-JAAM; SAND2018-9364J; PRBMDO
Journal Information:
Physical Review B, Vol. 98, Issue 8; ISSN 2469-9950
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 14 works
Citation information provided by
Web of Science

References (26)

Atomic-Scale Structure of Nanocrystalline Ba x Sr 1- x TiO 3 ( x = 1, 0.5, 0) by X-ray Diffraction and the Atomic Pair Distribution Function Technique journal February 2006
Emergence of Long-Range Order in BaTiO 3 from Local Symmetry-Breaking Distortions journal May 2016
Crystal stability and the theory of ferroelectricity journal October 1960
Rapid-acquisition pair distribution function (RA-PDF) analysis journal November 2003
The chain structure of BaTiO3 and KNbO3 journal October 1968
Désordre linéaire dans les cristaux (cas du silicium, du quartz, et des pérovskites ferroélectriques) journal March 1970
PDFFIT , a program for full profile structural refinement of the atomic pair distribution function journal June 1999
Local structure in perovskite ( Ba , Sr ) TiO 3 : Reverse Monte Carlo refinements from multiple measurement techniques journal January 2014
Local Structural Origins of the Distinct Electronic Properties of Nb-Substituted SrTiO 3 and BaTiO 3 journal November 2008
Ferroelectricity in Barium Titanate Quantum Dots and Wires journal December 2003
Synthesis of Tetragonal Barium Titanate Nanoparticles Via Alkoxide?Hydroxide Sol-Precipitation: Effect of Water Addition journal January 2007
PDFgetX3 : a rapid and highly automatable program for processing powder diffraction data into total scattering pair distribution functions journal March 2013
Quantitative size-dependent structure and strain determination of CdSe nanoparticles using atomic pair distribution function analysis journal September 2007
On the origin of ferroelectricity in perovskite-type crystals journal April 1966
The role of interfaces on an apparent grain size effect on the dielectric properties for ferroelectric barium titanate ceramics journal February 1998
PDFfit2 and PDFgui: computer programs for studying nanostructure in crystals journal July 2007
Temperature dependence of the A1 and E optical phonons in BaTiO3 journal February 1977
The ferroelectric and cubic phases in BaTiO3 ferroelectrics are also antiferroelectric journal September 2006
Dielectric properties of fine‐grained barium titanate ceramics journal August 1985
Structural Evolution of BaTiO 3 Nanocrystals Synthesized at Room Temperature journal May 2012
Crystal Structure and the Paraelectric-to-Ferroelectric Phase Transition of Nanoscale BaTiO 3 journal June 2008
Probing Local Dipoles and Ligand Structure in BaTiO 3 Nanoparticles journal August 2010
Local structure and the phase transitions of BaTiO 3 journal February 1998
Structures of the ferroelectric phases of barium titanate journal March 1993
Two-dimensional detector software: From real detector to idealised image or two-theta scan journal January 1996
Pair-distribution functions of ferroelectric perovskites: Direct observation of structural ground states journal February 1995