Thermodynamic investigation of the Ruddlesden-Popper phase Sr3Fe2O7

Publication date: Available online 20 January 2020Source: The Journal of Chemical ThermodynamicsAuthor(s): A.V. Knyazev, Yu.V. Alekseeva, N.N. Smirnova, O.V. Krasheninnikova, A.V. Markin, E.V. Syrov, E.V. Elipasheva, L.V. SmirnovaAbstractThe heat capacity of layered perovskite-like oxide Sr3Fe2O7 was measured for the first time by precision adiabatic vacuum calorimetry over the temperature range of (6–305) K and by differential scanning calorimetry in the range from 300 K to 420 K. The standard thermodynamic functions of the compound were evaluated from the experimental heat capacity temperature dependences over the range of (0–420) K. The phase transitions of the compound were studied by means of X-ray diffraction and differential scanning calorimetry. The main regularities of the thermal expansion of Sr3Fe2O7 are revealed. The mechanisms of the phase transitions at 120 K and 366 K are suggested. More significant structural changes were observed for metal-insulator transition. All transformations occur within the tetragonal symmetry of the unit cell.Graphical abstract

Source: The Journal of Chemical Thermodynamics - January 20, 2020 Category: Chemistry Source Type: research