Synthesis, X-Ray Diffraction Study, and Calorimetry
of Manganites NdM^ICaMn₂O₆ (M^I = Li, Na, K, Cs)

B. K. Kasenov, E. S. Mustafin, M. A. Isabaeva, Sh. B. Kasenova, Zh. I. Sagintaeva,
Zh. S. Bekturganov, and A. Nukhuly

Institute of Phytochemistry, Ministry of Education of Kazakhstan, Karaganda, Kazakhstan

e-mail: biblioteka@nursat.kz

Received November 4, 2004

Abstract—Manganites NdM^IMn₂O₆ (M^I = Li, Na, K, Cs) have been synthesized by the solid-phase method
from Nd₂O₃, Mn₂O₃ , calcium carbonate, and alkali-metal carbonates. These compounds crystallize in cubic
perovskite space group Pm3m. The heat capacities of the manganites have been studied by dynamical calorim-
etry in the temperature range 298.15–673 K. Abrupt heat capacity anomalies have been revealed. These anomalies
are probably associated with second-order phase transitions, which occur at 398 K in NdLiCaMn₂O₆ , at 373 K in
NdNaCaMn₂O₆ , at 373 and 523 K in NdKCaMn₂O₆ , and at 473 K in NdCsCaMn₂O₆ . The equations have been
derived to describe the ~ f (T) dependences and the temperature dependences of thermodynamic functions.

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