**Физика Низких Температур: ***Том ***44**, Выпуск **4** (Апрель 2018), c. 432-438
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### Pressure effect on magnetic susceptibility of LaCoO_{3}

**A.S. Panfilov, G.E. Grechnev, I.P. Zhuravleva, A.A. Lyogenkaya, and V.A. Pashchenko**

B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Nauky Ave., Kharkiv 61103, Ukraine

E-mail: panfilov@ilt.kharkov.ua; grechnev@ilt.kharkov.ua

**B.N. Savenko**

Joint Institute for Nuclear Research, Dubna 141980, Russia

**D. Novoselov**

M.N. Mikheev Institute of Metal Physics, Ural Branch of the Russian Academy of Sciences Yekaterinburg 620108, Russia

Ural Federal University, Yekaterinburg 620002, Russia

**D. Prabhakaran**

Department of Physics, University of Oxford, Oxford, OX1 3PU, Great Britain

**I.O. Troyanchuk**

Scientific-Practical Material Research Center, National Academy of Sciences of Belarus, Minsk 220072, Belarus

*Received December 21, 2017*

**Аннотация**

The effect of pressure on magnetic properties of LaCoO_{3} is studied experimentally and theoretically. The pressure dependence of magnetic susceptibility χ of LaCoO_{3} 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 LaCoO_{3}. 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 LaCoO_{3}. 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.

PACS: 71.20.Eh Rare earth metals and alloys;

PACS: 75.30.Mb Valence fluctuation, Kondo lattice, and heavy-fermion phenomena;

PACS: 75.80.+q Magnetomechanical effects, magnetostriction.

**Ключевые слова: **LaCoO_{3} compound, magnetic susceptibility, pressure effect, DFT+U calculations, spin states crossover.

**Published online:** *February 26, 2018*