The effect of temperature and pressure on the spin state of cobalt ions in La(1-x)Pr(x)CoO(3)compounds
authors Panfilov, AS; Lyogenkaya, AA; Grechnev, GE; Pashchenko, VA; Vasylechko, LO; Hreb, VM; Kovalevsky, AV
nationality International
journal LOW TEMPERATURE PHYSICS
author keywords RCoO(3)compounds; spin crossover; magnetic measurements; high-pressure effects; electronic structure calculations
keywords MAGNETIC-SUSCEPTIBILITY; TRANSITION; ANOMALIES; BEHAVIOR; PHASE; LA
abstract The crystal structure, magnetic susceptibility as a function of temperature chi(T) in the range 5-400 K, and the hydrostatic pressure effect on chi at fixed temperaturesT = 78, 150, and 300 K, were studied in perovskite-like compounds La1-xPrxCoO3(x = 0, 0.1, 0.2, and 0.3). The obtained experimental data were analyzed using a two-level model with an energy gap Delta between the ground and excited states of the system that correspond to the spin valuesS = 0 and 1 for Co(3+)ions. In this model, the magnetism of Co(3+)ions, which determines the features of the chi (T) dependence, is ensured by the temperature-induced change in the population of the excited state. The anomalously large magnitude of the observed pressure effect is associated with the high sensitivity of Delta to changes in the lattice volume, under the influence of both hydrostatic and chemical pressures, when La is replaced by the smaller Pr ion in the considered system. Theoretical calculations of the electronic structure for the boundary compounds LaCoO(3)and PrCoO(3)confirm the significant increase in the excitation energy Delta with a decrease in the lattice volume, and also support the scenario of a spin crossover between the states of cobalt ions with low and intermediate spin values.
publisher AMER INST PHYSICS
issn 1063-777X
year published 2020
volume 46
issue 6
beginning page 606
ending page 614
digital object identifier (doi) 10.1063/10.0001244
web of science category Physics, Applied
subject category Physics
unique article identifier WOS:000544655500008
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