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Title: High pressure floating zone growth and structural properties of ferrimagnetic quantum paraelectric BaFe{sub 12}O{sub 19}

High quality single crystals of BaFe{sub 12}O{sub 19} were grown using the floating zone technique in 100 atm of flowing oxygen. Single crystal neutron diffraction was used to determine the nuclear and magnetic structures of BaFe{sub 12}O{sub 19} at 4 K and 295 K. At both temperatures, there exist local electric dipoles formed by the off-mirror-plane displacements of magnetic Fe{sup 3+} ions at the bipyramidal sites. The displacement at 4 K is about half of that at room temperature. The temperature dependence of the specific heat shows no anomaly associated with long range polar ordering in the temperature range from 1.90 to 300 K. The inverse dielectric permittivity, 1/ε, along the c-axis shows a T{sup 2} temperature dependence between 10 K and 20 K, with a significantly reduced temperature dependence displayed below 10 K. Moreover, as the sample is cooled below 1.4 K there is an anomalous sharp upturn in 1/ε. These features resemble those of classic quantum paraelectrics such as SrTiO{sub 3}. The presence of the upturn in 1/ε indicates that BaFe{sub 12}O{sub 19} is a critical quantum paraelectric system with Fe{sup 3+} ions involved in both magnetic and electric dipole formation.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [5] ; ;  [2] ;  [6] ; ;  [2] ;  [3]
  1. Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
  2. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
  3. (United States)
  4. Department of Physics, Florida State University, Tallahassee, Florida 32306-3016 (United States)
  5. National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310-3706 (United States)
  6. Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States)
Publication Date:
OSTI Identifier:
22499229
Resource Type:
Journal Article
Resource Relation:
Journal Name: APL Materials; Journal Volume: 3; Journal Issue: 6; Other Information: (c) 2015 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIELECTRIC MATERIALS; ELECTRIC DIPOLES; IRON IONS; MONOCRYSTALS; NEUTRON DIFFRACTION; OXYGEN; PERMITTIVITY; SPECIFIC HEAT; TEMPERATURE DEPENDENCE; ZONE MELTING