EPR Study of Solid Solutions La_{1 0.33y}Ba_0.33yMn_yAl_{1 y}O₃
(y = 0.02, 0.04, 0.10)

S. I. Andronenko^a, R. R. Andronenko^b, *, and O. A. Zagrebel’nyi^a

^aKazan State University, ul. Kremlevskaya 18, Kazan, 420008 Russia

^bGrebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences,
nab. Admirala Makarova 2, St. Petersburg, 199034 Russia

* e-mail: roza@isc.nw.ru

Received October 26, 2009

Abstract—Solid solutions La_{1 – 0.33y}Ba_0.33yMn_yAl_{1 – y}O₃ (y = 0.02, 0.04, 0.10) prepared using the ceramic technique
have been investigated by the EPR method at temperatures of 77 and 300 K. By comparing with the calculated spectra,
the experimental spectra have been assigned to Mn²⁺ ions (g = 2.04 and line width H_pp = 64 10^–4 T at T=77K) and
Mn⁴⁺ ions (g = 1.97 and H_pp = 76 10^–4 T at T = 77 K) and the broad line (H_pp = 500 10^–4 T at T= 77 K) has been
attributed to clusters. The dilution of manganese ions as a result of the dissolution of La_0.67Ba_0.33MnO₃ in LaAlO₃ has
allowed one to trace the cluster formation and the spin dynamics of Mnions. It has been established that, at room tem-
perature, compared to the system in which the Sr²⁺ ion with a smaller ionic radius is the replacing element, the localized
states are more stable at all three manganese concentrations (the EPR lines are more intense). The La_0.67Ba_0.33MnO₃
clusters dissolved in LaAlO₃ retain some properties of a concentrated compound even upon dilution to y = 0.02.

Key words: manganites, magnetic resonance, EPR, Mn²⁺ and Mn⁴⁺ paramagnetic centers

DOI: 10.1134/S1087659610050111

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