Pressure effect on magnetic susceptibility of LaCoO₃

• Дата: 2018
• Автори: Panfilov, A.S., Grechnev, G.E., Zhuravleva, I.P., Lyogenkaya, A.A., Pashchenko, V.A., Savenko, B.N., Novoselov, D., Prabhakaran, D., Troyanchuk, I.O.
• Формат: Стаття
• Мова: English
• Опубліковано: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2018
• Назва видання: Физика низких температур
• Теми: Низкотемпеpатуpный магнетизм
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/175990
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Цитувати: Pressure effect on magnetic susceptibility of LaCoO₃ / A.S. Panfilov, G.E. Grechnev, I.P. Zhuravleva, A.A. Lyogenkaya, V.A. Pashchenko, B.N. Savenko, D. Novoselov, D. Prabhakaran, I.O. Troyanchuk // Физика низких температур. — 2018. — Т. 44, № 4. — С. 432-438. — Бібліогр.: 46 назв. — англ.

The effect of pressure on magnetic properties of LaCoO₃ is studied experimentally and theoretically. The pressure dependence of magnetic susceptibility χ of LaCoO₃ is obtained by precise measurements of χ as a function of the hydrostatic pressure P up to 2 kbar in the temperature range from 78 K to 300 K. A pronounced magnitude of the pressure effect is found to be negative in sign and strongly temperature dependent. The obtained experimental data are analysed by using a two-level model and DFT+U calculations of the electronic structure of LaCoO₃ . In particular, the fixed spin moment method was employed to obtain a volume dependence of the total energy difference Δ between the low spin and the intermediate spin states of LaCoO₃ . Analysis of the obtained experimental χ(P) dependence within the two-level model, as well as our DFT+U calculations, have revealed the anomalous large decrease in the energy difference Δ with increasing of the unit cell volume. This effect, taking into account a thermal expansion, can be responsible for the temperatures dependence of Δ, predicting its vanishing near room temperature.