English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report on the magnetic, resistive, and structural studies of perovskiteLa$_{1/3}$Sr$_{2/3}$CoO$_{3-\delta}$. By using the relation of synthesistemperature and oxygen partial pressure to oxygen stoichiometry obtained fromthermogravimetric analysis, we have synthesized a series of samples withprecisely controlled $\delta=0.00-0.49$. These samples show three structuralphases at $\delta=0.00-0.15$, $\approx0.25$, $\approx0.5$, and two-phasebehavior for other oxygen contents. The stoichiometric material with$\delta=0.00$ is a cubic ferromagnetic metal with the Curie temperature $T_{\rmC}=274$ K. The increase of $\delta$ to 0.15 is followed by a linear decrease of$T_{\rm C}$ to $\approx$ 160 K and a metal-insulator transition near theboundary of the cubic structure range. Further increase of $\delta$ results information of a tetragonal $2a_p\times 2a_p \times 4a_p$ phase for$\delta\approx 0.25$ and a brownmillerite phase for $\delta\approx0.5$. At lowtemperatures, these are weak ferromagnetic insulators (canted antiferromagnets)with magnetic transitions at $T_{\rm m}\approx230$ and 120 K, respectively. Athigher temperatures, the $2a_p\times 2a_p \times 4a_p$ phase is $G$-typeantiferromagnetic between 230 K and $\approx$360 K. Low temperature magneticproperties of this system for $\delta<1/3$ can be described in terms of amixture of Co$^{3+}$ ions in the low-spin state and Co$^{4+}$ ions in theintermediate-spin state and a possible spin transition of Co$^{3+}$ to theintermediate-spin state above $T_{\rm C}$. For $\delta>1/3$, there appears tobe a combination of Co$^{2+}$ and Co$^{3+}$ ions, both in the high-spin statewith dominating antiferromagnetic interactions.Comment: RevTeX, 9 pages, 7 figures, to be published in Physical Review

Tuning of magnetic and electronic states by control of oxygen content in lanthanum strontium cobaltites