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Effects of Temperature and Pressure on the Magnetic Properties of La 1– x Pr x CoO 3
Author(s) -
Panfilov Anatoliy S.,
Lyogenkaya Anastasiya A.,
Grechnev Gennadiy E.,
Pashchenko Volodymyr A.,
Vasylechko Leonid O.,
Hreb Vasyl M.,
Kovalevsky Andrei V.
Publication year - 2020
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.202000085
Subject(s) - ionic radius , hydrostatic pressure , excited state , magnetism , magnetic susceptibility , ion , ground state , chemistry , atmospheric temperature range , population , condensed matter physics , crystal structure , atomic physics , thermodynamics , crystallography , physics , demography , organic chemistry , sociology
For La 1– x Pr x CoO 3 cobaltites ( x = 0, 0.1, 0.2, and 0.3), the dependence of magnetic susceptibility χ ( T ) is studied in the temperature range 5–400 K. Also, the crystal structure of these cobaltites is investigated, and the effect of pressure up to 2 kbar on their susceptibility is measured at T = 78 , 150, and 300 K. The specific dependencies χ ( T ) and the large negative pressure effect are assumed to arise from Co 3+ ions contribution to the total susceptibility evaluated using La 1− x Pr x AlO 3 as a reference system. The obtained experimental data on temperature and pressure effects in magnetism are analyzed within a two‐level model with energy gap Δ between the ground state of the system with zero spin of Co 3+ ions and the excited higher‐spin state. In this model, magnetism of Co 3+ ions is determined by the temperature‐induced population of the excited state, and magnitude of the pressure effect is governed by the volume dependence of Δ. The results of the analysis, supplemented by the theoretical calculations of the electronic structures of LaCoO 3 and PrCoO 3 , indicate significant increase in Δ with decrease in the unit cell volume both under hydrostatic pressure and by substituting La with Pr having a smaller ionic radius.