Structural anomalies associated with the electronic and spin transitions in LnCoO3

Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y–Ba–Co–O system

“…According to Xray diffraction it was found that after 120 h annealing at 1173 K in air YCoO 3−δ possesses orthorhombically distorted perovskite structure (sp.gr. Pbnm) [13][14][15][16][17][18]. The unit cell parameters presented by Jadhao et al a ¼5.132 Å, b ¼5.417 Å, с ¼7.367 Å [16], were in good agreement with the data reported in [12,14,15].…”

“…According to the results of XRD the sample with x¼ 0 consisted of Y 2 O 3 and CoO as expected since YCoO 3−δ is usually prepared and investigated at temperatures that do not exceed 1173 K [13][14][15][16][17]. On the other side the sample with x¼1 was single phase BaCoO 3−δ crystallized in hexagonal structure with the unit cell parameters а¼5.665 Å, c¼28.493 Å (sp.…”

“…It was prepared by standard ceramic technique under high (50-70 kbar) oxygen pressure [12], or at 1173 K during 100 h in the oxygen flow [13][14][15], or by the decomposition of yttrium and cobalt cyanides [16], or by sol-gel method [17,18]. According to Xray diffraction it was found that after 120 h annealing at 1173 K in air YCoO 3−δ possesses orthorhombically distorted perovskite structure (sp.gr.…”

“…Pbnm) [13][14][15][16][17][18]. The unit cell parameters presented by Jadhao et al a ¼5.132 Å, b ¼5.417 Å, с ¼7.367 Å [16], were in good agreement with the data reported in [12,14,15]. According to Demazeau et al [12] yttrium cobaltate YCoO 3−δ decomposes in air at temperature higher 1123 K, however synthesis conditions used in [13][14][15] make it possible to conclude that decomposition temperature probably exceeds 1173 K. Y 2 BaO 4 [19][20][21], Y 4 Ba 3 O 9 [19,20] [20,21].…”

Perovskitas manganitas con Mn sustituido TRCo_xMn_1-xO₃: comparación entre las propiedades magnéticas de LaCo_xMn_1-xO₃ y de GdCo_xMn_1-xO₃

“…These pure cobaltites have been thoroughly studied because of the magnetic-electronic transitions observed at low and high temperatures and the different anomalies associated to them (21,22). It is by now established that a spin transition occurs from a low-temperature low-spin LS state Co III (t ; S = 1) has been also suggested (22).…”