Neutron-diffraction studies of the antiferromagnetic–ferromagnetic transition in anion-deficient cobaltites

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• 作者：V. V. Sikolenko ; V. V. Efimov ; E. A. Efimova…
• 关键词：neutron diffraction ; magnetic structure ; pressure
• 刊名：Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：10
• 期：6
• 页码：1133-1135
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Surfaces and Interfaces, Thin Films;
• 出版者：Pleiades Publishing
• ISSN：1819-7094
• 卷排序：10

文摘

Anion-deficient La_0.5Ba_0.5CoO_2.8 and Y_0.25Ca_0.25Sr_0.5CoO_2.62 cobaltites are studied under pressures up to 6.5 GPa in the temperature range of 5−300 K by neutron powder diffraction. Under ambient pressure both compounds are antiferromagnetic with T_N = 250 K. The applied pressure induces in the first compound a gradual transition from the antiferromagnetic to ferromagnetic state through a mixed magnetic state, whereas the second compound remains antiferromagnetic in the whole pressure range. We suggest that the magnetic ground state depends on the unit-cell volume and the magnetic transition is associated with the transition of cobalt ions from the mixed high-spin/low-spin state to the intermediate-spin/low-spin state.