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High‐pressure phase transitions in the rare‐earth orthoferrite LaFeO 3
Author(s) -
Etter Martin,
Müller Melanie,
Hanfland Michael,
Dinnebier Robert E.
Publication year - 2014
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520614007379
Subject(s) - orthoferrite , bulk modulus , phase transition , materials science , rietveld refinement , powder diffraction , isostructural , diffraction , lanthanum , crystallography , thermodynamics , condensed matter physics , crystal structure , chemistry , magnetization , inorganic chemistry , composite material , physics , optics , quantum mechanics , magnetic field
Sequential Rietveld refinements were applied on high‐pressure synchrotron powder X‐ray diffraction measurements of lanthanum ferrite (LaFeO 3 ) revealing two phase transitions on the room‐temperature isotherm up to a pressure of 48 GPa. The first structural phase transition of second order occurs at a pressure of 21.1 GPa, changing the space group from Pbnm to Ibmm . The second transition, involving a isostructural first‐order phase transition, occurs at approximately 38 GPa, indicating a high‐spin to low‐spin transition of the Fe 3+ ion. Following the behavior of the volume up to the hydrostatic limit of methanol–ethanol it was possible to use inverted equations of state (EoS) to determine a bulk modulus of B 0 = 172 GPa and a corresponding pressure derivative of B ′ 0 = 4.3. In addition, the linearized version of the inverted EoS were used to determine the corresponding moduli and pressure derivatives for each lattice direction.