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arXiv · 1801.01325

Pressure effect on magnetic susceptibility of LaCoO$_3$

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
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Abstract

The effect of pressure on magnetic properties of LaCoO$_3$ is studied experimentally and theoretically. The pressure dependence of magnetic susceptibility $\chi$ of LaCoO$_3$ is obtained by precise measurements of $\chi$ 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 $\Delta$ between the low spin and the intermediate spin states of LaCoO$_3$. Analysis of the obtained experimental $\chi(P)$ dependence within the two-level model, as well as our DFT+U calculations, have revealed the anomalous large decrease in the energy difference $\Delta$ with increasing of the unit cell volume. This effect, taking into account a thermal expansion, can be responsible for the temperatures dependence of $\Delta$, predicting its vanishing near room temperature.

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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. 2018-01-04. Pressure effect on magnetic susceptibility of LaCoO$_3$. https://doi.org/10.1063/1.5030456

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