Toward oxygen fully stoichiometric La1-xSrxCoO3 (0.5≤x≤0.9) perovskites: Itinerant magnetic mechanism more than double exchange one's

Madhu Chennabasappa (1) , Emmanuel Petit (1) , Olivier Toulemonde (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

We report a two steps synthesis of strontium rich cobaltates La1-xSrxCoO3-δ (0.5 ≤ x ≤ 0.9) compounds. Following the standard solid state procedure, an oxygen intercalation process has been carried out. All the compounds show a perovskite related type structure. Samples have been characterized from chemical and structural point of view. The cubic “a” cell parameter saturates with the oxygen deficiency parameters δ that is controlled by the thermodynamic parameters (pO2; T). The magnetic properties studies were carried out before and after oxygen intercalation process and a continuous transfer from a localized character to an itinerant one's when oxygen is up taken is supported. A complete magnetic phase diagram with respect to temperature is proposed. One further evidence for attaining of Co+3.58 against Co+3.70 in La0.3Sr0.7CoO3-δ with the help of electrochemical oxidation that definitively both metal like behavior and higher than 280 K paramagnetic to ferromagnetic temperature phase transition unambiguously signed an oxygen stoichiometry close to 3 in La1-xSrxCoO3 perovskites serie.

Mots clés: La1-xSrxCoO3 perovskite; Cobaltates; Double exchange; Itinerant magnetism; Electrochemical oxidation 2

Domaines: Matériaux

Madhu Chennabasappa, Emmanuel Petit, Olivier Toulemonde. Toward oxygen fully stoichiometric La1-xSrxCoO3 (0.5≤x≤0.9) perovskites: Itinerant magnetic mechanism more than double exchange one's. Ceramics International, 2020, 46 (5), pp.6067-6072. ⟨10.1016/j.ceramint.2019.11.067⟩. ⟨hal-02613653⟩