Thermochemistry of perovskites in the lanthanum–strontium–manganese–iron oxide system

Abstract

of Perovskites in the lanthanumstrontium-manganese-iron oxide system, Journal of Solid State Chemistry, http://dx.Abstract The enthalpies of formation from binary oxides of perovskites (ABO 3 ) based on lanthanum strontium manganite La(Sr)MnO 3 (LSM) and lanthanum strontium ferrite La(Sr)FeO 3 (LSF) and mixed lanthanum strontium manganite ferrite La(Sr)Mn(Fe)O 3 (LSMF) were measured by high temperature oxide melt solution calorimetry. Using iodometric titration, the oxygen content was derived. The perovskites with A-site cation deficiency have greater oxygen deficiency than the corresponding A-site stoichiometric series. Stability of LSMF decreases with increasing iron content. Increasing oxygen deficiency clearly destabilizes the perovskites. The results suggest an enthalpy of oxygen incorporation that is approximately independent of composition.

Isothermal redox cycling of A‐ and B‐site substituted manganite‐based perovskites for CO2 conversion

“…Research has shown that the magnetic and transport properties of La 1-x Sr x Mn 1-y Fe y O 3 perovskites are influenced by the Fe content. [18] Similarly, oxygen carriers based on Fe have displayed strong activity for H 2 O splitting as well as for total oxidation of CH 4 . [19] La 1-x Sr x FeO 3 have illustrated strong stability and repeatability for the oxidation of CH 4 .…”

Role of Na2CO3 Addition in Epitaxial Growth of Ruby Crystal Films on Sapphire Crystal Substrates via MoO3 Flux Evaporation

“…A 2 CO 3 generates carbon dioxide (CO 2 ) when it reacts with MoO 3 , and A 2 O–MoO 3 are produced. A 2 O–MoO 3 is a well-known oxide solvent, which is widely used for the high temperature calorimetry of complex oxides. − The suppression of evaporation of MoO 3 flux by A 2 CO 3 and the growth of large crystals are empirically known, but its mechanism is not elucidated. The effect of inhibitor addition on evaporation rate of flux and growth rate of ruby crystal films should be further investigated.…”

The Effects of External Magnetic Field on the Physical Properties of La_0.41Ca_0.59Mn_1-xCu_xO₃ with x = 0.06 and 0.15 in the Temperature Range of 100 – 300 K

“…are still intensively studied. Works focusing on various physical properties of the compounds, such as magnetoresistance (MR), crystal structure change, metal-insulator transition, specific heat, large magneto-caloric effect, and high electrical conductivity have been reported [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. These rare … (T MI ) of about 243 K. In case of T>T MI , the resisitivity as a function of temperature could be described by two different models, namely the variable range hopping (VRH) model or Arhenius model and the adiabatic small polaron hopping (ASPH) model but more in line with the second model (ASPH).…”

“…At the temperature less than 184 K, the resisitivity follows the Arhenius model (ln R varies as 1/T 0.25 ) while at higher temperatures it fits the metal-semiconductor model (ln R varies as 1/T). The electronic specific heat parameter γ varies with magnetic field at x = 0.06, but not at x = 0.15. earths manganite compounds have found a wide range of application, such as a mild hyperthermia mediator [1], magnetic refrigeration technology near room temperature [5], and a fuel cell cathode [7][8][9].Until now, the results of measurements and analysis of this material still make a lot of differences. Suppose La 1-x Sr x MnO 3 will change from orthorhombic (x<0.2) to rhombohedral (x>0.2) [1], at low temperatures, La 1-x Ca x MnO 3 structure will change from cubic to rhombohedral then to orthorhombic [2], while La 0.65 Ca 0.35-x Ba x MnO 3 has a rhombohedral crystal structure for x<0.15 and a cubic for 0.15<x<0.25 [3].…”

“…At the temperature less than 184 K, the resisitivity follows the Arhenius model (ln R varies as 1/T 0.25 ) while at higher temperatures it fits the metal-semiconductor model (ln R varies as 1/T). The electronic specific heat parameter γ varies with magnetic field at x = 0.06, but not at x = 0.15. earths manganite compounds have found a wide range of application, such as a mild hyperthermia mediator [1], magnetic refrigeration technology near room temperature [5], and a fuel cell cathode [7][8][9].…”