title: High-pressure phase transitions in the rare-earth orthoferrite LaFeO3.
abstract: Sequential Rietveld refinements were applied on high-pressure synchrotron powder X-ray diffraction measurements of lanthanum ferrite (LaFeO3) 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 B0 = 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.
authors.affiliation: Max Planck Institute for Solid State Research, Stuttgart, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Etter
authors.affiliation: Max Planck Institute for Solid State Research, Stuttgart, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Müller
authors.affiliation: European Synchrotron Radiation Facility (ESRF), Grenoble, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Hanfland
authors.affiliation: Max Planck Institute for Solid State Research, Stuttgart, Germany.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Dinnebier