Comparative study of ordered and disordered Y1−xSrxCoO3−δ

Abstract

We have succeeded in preparing A-site ordered and disordered Y1∕4Sr3∕4CoO3−δ with various oxygen deficiencies δ, and have made a comparative study of their structural and physical properties. In the A-site ordered structure, oxygen vacancies order, and δ=0.34 sample shows a weak ferromagnetic transition beyond 300K. On the other hand, in the A-site disordered structure, no oxygen-vacancy ordering is observed, and δ=0.16 sample shows a ferromagnetic metallic transition around 150K. A-site disordering destroys the orderings of oxygen vacancies and orbitals, leading to the strong modification of the electronic phases.

Microstructure and electrical conductivity of (Y, Sr)CoO 3-δ thin films tuned by the film-growth temperature

“…Y x Sr 1−x CoO 3−δ (YSCO) compounds with room-temperature ferromagnetic properties were reported [19−23]. In particular, the YSCO compound with x≈0.25 exhibits the highest Curie temperature (T c ≈335 K) among the perovskite-based cobaltates and the properties of YSCO could be modulated by its chemical composition [24,25]. In contrast to the considerable studies on the YSCO bulk materials, investigations on the microstructure and the properties of the YSCO thin films are limited [19−26].…”

Complex room-temperature ferrimagnetism induced by zigzag stripes of oxygen vacancies inSr3YCo4O10+δKhalyavin1, Chapon2, Suard3 et al. 2011Phys. Rev. B343410View full textAdd to dashboardCite

“…The latter ordering produces an alternate stacking of oxygen-rich octahedral (CoO 6 ) layers and oxygendeficient tetrahedral (CoO 4 ) layers along the c-axis. For compositions with 0.5 < δ < 1, an additional superstructure has been identified (2 √ 2a p × 2 √ 2a p × 4a p ) and attributed to the ordering of the extra oxygen ions in the CoO 4+δ layers.3-7 It has been shown 6,8,9 that the formation of such superstructure is key to the appearance of ferromagnetism; however a clear understanding of its microscopic origin is still missing in spite of several neutron diffraction studies.10-15 The main difficulty lies in the simultaneous determination of the oxygen ordering …”

“…3-7 It has been shown 6,8,9 that the formation of such superstructure is key to the appearance of ferromagnetism; however a clear understanding of its microscopic origin is still missing in spite of several neutron diffraction studies.…”

Effects of partial Co replacement by Fe in Sr0.775Y0.225CoO3-δ on its magnetic property, oxygen deficiency and crystal structure

“…These so-called ordered 314 phase structure, associated with the Sr 0.75 Y 0.25 CoO 3−δ stoichiometric formula, apparently resembles the Brownmillerite structure found in the mineral Ca 2 [Fe,Al] 2 O 5 which also consists of alternating layers of tetrahedral and octahedral. In the 314 structure, however, the Co ions in the tetrahedral section form the tetracyclic Co 4 O 12 units due to Sr 2+ and Y 3+ ordering, instead of the formation of infinite Co chains in the tetrahedral section found in the brownmillerite structure [14,33].…”