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Title: Polar state in freestanding strontium titanate nanoparticles

Abstract

Monodispersed strontium titanate nanoparticles were prepared and studied in detail. It is found that ∼10 nm as-prepared stoichiometric nanoparticles are in a polar structural state (possibly with ferroelectric properties) over a broad temperature range. A tetragonal structure, with possible reduction of the electronic hybridization, is found as the particle size is reduced. In the 10 nm particles, no change in the local Ti-off centering is seen between 20 and 300 K. The results indicate that nanoscale motifs of SrTiO{sub 3} may be utilized in data storage as assembled nano-particle arrays in applications where chemical stability, temperature stability, and low toxicity are critical issues.

Authors:
;  [1];  [2]; ;  [3];  [4]; ;  [5];  [3];  [6]
  1. Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)
  2. Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)
  3. Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794 (United States)
  4. Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973 (United States)
  5. Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)
  6. (United States)
Publication Date:
OSTI Identifier:
22311013
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 9; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; FERROELECTRIC MATERIALS; NANOPARTICLES; NANOSTRUCTURES; PARTICLE SIZE; STABILITY; STOICHIOMETRY; STRONTIUM TITANATES; TOXICITY

Citation Formats

Tyson, Trevor A., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu, Yu, Tian, Croft, Mark, Scofield, Megan E., Bobb-Semple, Dara, Tao, Jing, Jaye, Cherno, Fischer, Daniel, Wong, Stanislaus S., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu, and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973. Polar state in freestanding strontium titanate nanoparticles. United States: N. p., 2014. Web. doi:10.1063/1.4894253.
Tyson, Trevor A., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu, Yu, Tian, Croft, Mark, Scofield, Megan E., Bobb-Semple, Dara, Tao, Jing, Jaye, Cherno, Fischer, Daniel, Wong, Stanislaus S., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu, & Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973. Polar state in freestanding strontium titanate nanoparticles. United States. doi:10.1063/1.4894253.
Tyson, Trevor A., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu, Yu, Tian, Croft, Mark, Scofield, Megan E., Bobb-Semple, Dara, Tao, Jing, Jaye, Cherno, Fischer, Daniel, Wong, Stanislaus S., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu, and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973. Mon . "Polar state in freestanding strontium titanate nanoparticles". United States. doi:10.1063/1.4894253.
@article{osti_22311013,
title = {Polar state in freestanding strontium titanate nanoparticles},
author = {Tyson, Trevor A., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu and Yu, Tian and Croft, Mark and Scofield, Megan E. and Bobb-Semple, Dara and Tao, Jing and Jaye, Cherno and Fischer, Daniel and Wong, Stanislaus S., E-mail: tyson@njit.edu, E-mail: sswong@bnl.gov, E-mail: Stanislaus.wong@stonybrook.edu and Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973},
abstractNote = {Monodispersed strontium titanate nanoparticles were prepared and studied in detail. It is found that ∼10 nm as-prepared stoichiometric nanoparticles are in a polar structural state (possibly with ferroelectric properties) over a broad temperature range. A tetragonal structure, with possible reduction of the electronic hybridization, is found as the particle size is reduced. In the 10 nm particles, no change in the local Ti-off centering is seen between 20 and 300 K. The results indicate that nanoscale motifs of SrTiO{sub 3} may be utilized in data storage as assembled nano-particle arrays in applications where chemical stability, temperature stability, and low toxicity are critical issues.},
doi = {10.1063/1.4894253},
journal = {Applied Physics Letters},
number = 9,
volume = 105,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}
  • Phase stability of the ferroelectric materials at high temperature is extremely important to their device performance. Ba{sub x}Sr{sub 1−x}TiO{sub 3} (BST) nanoparticles with different Sr contents (x = 1, 0.91, 0.65, 0.4, and 0) are prepared by a facile hydrothermal method. Using Raman spectroscopy and transmission electron microscopy (TEM) analyses under in situ heating conditions (up to 300 °C), the phase transitions of BST nanoparticles between 25 °C and 280 °C are comprehensively investigated. The original Curie temperature of BST nanoparticles decreases abruptly with the increase in Sr content, which is more obvious than in the bulk or film material. Besides, an abnormal phase transitionmore » from cubic to tetragonal structure is observed from BST nanoparticles and the transition temperature rises along with the increase in Sr content. Direct TEM evidences including a slight lattice distortion have been provided. Differently, BaTiO{sub 3} nanoparticles remained in the tetragonal phase during the above temperature ranges.« less
  • This paper reports the particle and crystallite size characterizations of mechanically alloyed Ba{sub (1-x)}Sr{sub x}TiO{sub 3} (BST) with x = 0.3 and 0.7 prepared with the assistance of a high-power sonicator. Analytical grade BaCO{sub 3}, TiO{sub 2} and SrCO{sub 3} precursors with a purity of greater than 99 wt.% were mixed and milled using a planetary ball mill to a powder weight ratio of 10:1. Powders obtained after 20 hours of milling time were then sintered at 1200°C for 4 hours to form crystalline powders.These powders were further treated ultrasonically under a fixed 6.7 gr/l particle concentration in demineralized watermore » for 1, 3, 5, 7 hours and a fixed ultrasonic irradiation time of 1 hour to the dispersion of 6.7; 20; 33.3 gr/l concentrations. As to the results of crystallite size characterization, it is demonstrated that the mean crystallite size of BST with x = 0.3 and 0.7 undergo a slight change after the first 1 hour irradiation time and then remain almost unchanged. This was in contrary to the particle size in which the mean particle size of BST with x = 0.3 increased from 765 nm to 1405 nm after 7 hours irradiation time, while that of x = 0.7 increased from 505 nm to 1298 nm after 3 hours and then reduced back to the initial size after 7 hours ultra sonication time. The increase in particle size was due to large of cohesive forces among fine particles. It is also demonstrated that the concentration of particles in a dispersion with anionic surfactant do not effective to reduce the particle sizes ultrasonically. Nanoparticles with the mean size respectively 40 and 10 times larger than their respective crystallite size were successfully obtained respectively in x = 0.3 and x = 0.7.« less
  • Barium Strontium Titanate (Ba{sub 1-x}Sr{sub x}TiO{sub 3}) or BST was prepared by solid state reaction method. Raw materials are BaCO{sub 3}, SrCO{sub 3}, and TiO{sub 2}. Those materials are mixed for 8 h, pressed, and sintered at temperature 1200°C for 2 h. Mole composition of Sr (x) was varied to study its influences on structural, morphological, and electrical properties of BST. Variation of (x) are x = 0; x = 0.1; and x = 0.5. XRD patterns showed a single phase of BST, which mean that mixture of raw materials was homogenous. Crystal structure was influenced by x. BaTiO{sub 3} and Ba{submore » 0.9}Ti{sub 0.1}TiO{sub 3} have tetragonal crystal structure, while Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} is cubic. The diffraction angle shifted to right side (angle larger) as the increases of x. Crystalline size of BaTiO{sub 3}, Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3}, and Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} are 38.13 nm; 38.62 nm; and 37.13 nm, respectively. SEM images showed that there are still of pores which were influenced by x. Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} has densest surface (pores are few and small in size). Sawyer Tower circuit showed that BaTiO{sub 3} and Ba{sub 0.9}Sr{sub 0.1} TiO{sub 3} is ferroelectric, while Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} is paraelectric. The dielectric constants of BaTiO{sub 3}, Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} and Ba{sub 0.5}Sr{sub 0.5}TiO{sub 3} at frequency of 1 KHz are 156; 196; and 83, respectively. Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} has relatively highest dielectric constant. It is considered that Ba{sub 0.9}Sr{sub 0.1}TiO{sub 3} has densest surface.« less