Pressure effect on magnetic susceptibility of LaCoO3
Ключові слова:LaCoO3 compound, magnetic susceptibility, pressure effect, DFT U calculations, spin states crossover.
АнотаціяThe 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.
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Panfilov, A.; Grechnev, G.; Zhuravleva, I.; Lyogenkaya, A.; Pashchenko, V.; Savenko, B.; Novoselov, D.; Prabhakaran, D.; Troyanchuk, I. Pressure Effect on Magnetic Susceptibility of LaCoO3. Fiz. Nyzk. Temp. 2018, 44, 432-438.