Heat capacity studies of magnetic phase transition in sodium-rich NaxCoO₂ (0.73 ≤ x ≤ 0.87)

• Дата: 2009
• Автори: Baran, A., Botko, M., Zorkovská, A., Kajňaková, M., Šebek, J., Šantavá, E., Peng, J.P., Lin, C.T., Feher, A.
• Формат: Стаття
• Мова: English
• Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2009
• Назва видання: Физика низких температур
• Теми: Низкотемпеpатуpный магнетизм
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/117413
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Heat capacity studies of magnetic phase transition in sodium-rich NaxCoO₂ (0.73 ≤ x ≤ 0.87) / A. Baran, M. Botko, A. Zorkovská, M. Kajňaková, J.Šebek, E. Šantavá, J.P. Peng, C.T. Lin, A. Feher // Физика низких температур. — 2009. — Т. 35, № 10. — С. 1030-1033. — Бібліогр.: 29 назв. — англ.

Specific heat measurements in the temperature region from 2 to 50 K in magnetic field up to 10 T, oriented parallel and perpendicularly to the CoO₂ layers were carried out on a series of high-quality single- crystals of NaxCoO₂ (x = 0.73, 0.76, 0.77, 0.78 and 0.87). Surprisingly, sharp lambda type anomaly was observed only for the concentration x = 0.76 at temperature (21.80 ± 0.02) K, for all the remaining doping levels round anomaly in experimental data was visible at temperature ~ 20 K, indicating a smeared magnetic phase transition. While the magnetic field oriented perpendicularly to the CoO₂ layers shifts the temperature of this anomaly to lower values, parallel magnetic field has no influence on it, what indirectly supports the idea of A-type antiferromagnetic ordering in studied systems.