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Title: Temperature- and pressure-driven spin-state transitions in LaCoO{sub 3}

Abstract

Crystal structure, spin state, and semiconductor-metal transitions of LaCoO{sub 3} in the 10-905 K temperature range were studied by neutron diffraction at high pressures up to 4.5 GPa and x-ray diffraction and Raman spectroscopy at high pressures up to 17.5 GPa. The susceptibility and thermal-expansion anomalies in the studied pressure range can be described successfully by the thermal excitation of two orbitally nondegenerate magnetic states with different electronic configuration, intermediate spin (IS), and high spin (HS) from the low-spin (LS) nonmagnetic ground state. The pressure-induced compression of Co-O bonds leads to a substantial increase of LS-IS and LS-HS energy splittings E{sub 1} and E{sub 2} with d ln E{sub 1}/dP=0.37 and d ln E{sub 2}/dP=0.23 GPa{sup -1}. The onset of the semiconductor-metal (S-M) transition in LaCoO{sub 3} correlates with the vanishing of several Raman modes forbidden for rhombohedral R3c symmetry and originating from local distortions due to short-range e{sub g}-orbital order of IS Co{sup 3+} ions. The S-M transition temperature increases rapidly under pressure with dT{sub S-M}/dP{approx_equal}50 K/GPa.

Authors:
; ;  [1];  [2];  [3];  [4];  [5];  [6]
  1. Frank Laboratory of Neutron Physics, JINR, 141980 Dubna (Russian Federation)
  2. Institute of Physics, Cukrovarnicka 10, 162 53 Prague 6 (Czech Republic)
  3. Bayerisches Geoinstitut, Universitaet Bayreuth, Bayreuth, D-95440 (Germany)
  4. ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxon, OX11 0QX (United Kingdom)
  5. Physique des Milieux Condenses, Universite P and M Curie, B77, 4 Place Jussieu, 75252 Paris (France)
  6. Russian Research Center 'Kurchatov Institute', 123182 Moscow (Russian Federation)
Publication Date:
OSTI Identifier:
20976689
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevB.75.064422; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CALCIUM NITRIDES; COBALT IONS; ELECTRONIC STRUCTURE; EXCITATION; GROUND STATES; LANTHANUM COMPOUNDS; MAGNETIC SUSCEPTIBILITY; NEUTRON DIFFRACTION; PARAMAGNETISM; PRESSURE RANGE GIGA PA; PRESSURE RANGE MEGA PA 10-100; RAMAN SPECTRA; RAMAN SPECTROSCOPY; SEMICONDUCTOR MATERIALS; SPIN; THERMAL EXPANSION; TRANSITION ELEMENTS; TRANSITION TEMPERATURE; TRIGONAL LATTICES; X-RAY DIFFRACTION

Citation Formats

Kozlenko, D. P., Golosova, N. O., Savenko, B. N., Jirak, Z., Dubrovinsky, L. S., Tucker, M. G., Le Godec, Y., and Glazkov, V. P. Temperature- and pressure-driven spin-state transitions in LaCoO{sub 3}. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.064422.
Kozlenko, D. P., Golosova, N. O., Savenko, B. N., Jirak, Z., Dubrovinsky, L. S., Tucker, M. G., Le Godec, Y., & Glazkov, V. P. Temperature- and pressure-driven spin-state transitions in LaCoO{sub 3}. United States. doi:10.1103/PHYSREVB.75.064422.
Kozlenko, D. P., Golosova, N. O., Savenko, B. N., Jirak, Z., Dubrovinsky, L. S., Tucker, M. G., Le Godec, Y., and Glazkov, V. P. Thu . "Temperature- and pressure-driven spin-state transitions in LaCoO{sub 3}". United States. doi:10.1103/PHYSREVB.75.064422.
@article{osti_20976689,
title = {Temperature- and pressure-driven spin-state transitions in LaCoO{sub 3}},
author = {Kozlenko, D. P. and Golosova, N. O. and Savenko, B. N. and Jirak, Z. and Dubrovinsky, L. S. and Tucker, M. G. and Le Godec, Y. and Glazkov, V. P.},
abstractNote = {Crystal structure, spin state, and semiconductor-metal transitions of LaCoO{sub 3} in the 10-905 K temperature range were studied by neutron diffraction at high pressures up to 4.5 GPa and x-ray diffraction and Raman spectroscopy at high pressures up to 17.5 GPa. The susceptibility and thermal-expansion anomalies in the studied pressure range can be described successfully by the thermal excitation of two orbitally nondegenerate magnetic states with different electronic configuration, intermediate spin (IS), and high spin (HS) from the low-spin (LS) nonmagnetic ground state. The pressure-induced compression of Co-O bonds leads to a substantial increase of LS-IS and LS-HS energy splittings E{sub 1} and E{sub 2} with d ln E{sub 1}/dP=0.37 and d ln E{sub 2}/dP=0.23 GPa{sup -1}. The onset of the semiconductor-metal (S-M) transition in LaCoO{sub 3} correlates with the vanishing of several Raman modes forbidden for rhombohedral R3c symmetry and originating from local distortions due to short-range e{sub g}-orbital order of IS Co{sup 3+} ions. The S-M transition temperature increases rapidly under pressure with dT{sub S-M}/dP{approx_equal}50 K/GPa.},
doi = {10.1103/PHYSREVB.75.064422},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 6,
volume = 75,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2007},
month = {Thu Feb 01 00:00:00 EST 2007}
}