Joint Institute for Nuclear Research, Dubna 141980, Russia
M.N. Mikheev Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences Yekaterinburg 620108, Russia Ural Federal University, Yekaterinburg 620002, Russia
Department of Physics, University of Oxford, Oxford, OX1 3PU, Great Britain
Scientific-Practical Material Research Center, National Academy of Sciences of Belarus, Minsk 220072, Belarus
Received December 21, 2017
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.