Spontaneous Generation of Voltage in Sm_0.55Sr_0.45MnO₃ and La_0.75Ba_0.25MnO₃ Single Crystals

Abstract:

In Sm_0.55Sr_0.45MnO₃ single crystals, grown by the floating-zone method with the cooling in oxygen, has been observed the spontaneous generation of voltage (SGV). Its maximum reaches 60 μV and occurs in the temperature range where simultaneous decay of the CE-type antiferromagnetic order and the charge order take place in some clusters. The SGV peak becomes lower by about 45% if magnetic field 14.2 kOe applied. Also we observed the SGV in La_0.75Ba_0.25MnO₃ single crystals. Maximum value of SGV occurs in a vicinity of the Curie temperature. The SGV value seems to be almost independent from the cooling or heating rate and crystallographic direction, but in La_0.75Ba_0.25MnO₃ it is smaller than in Sm_0.55Sr_0.45MnO₃ by an order of magnitude. La_0.75Ba_0.25MnO₃ compound contains ferromagnetic clusters, in which the electrical charges are localized according to gain in the s-d exchange energy. They are distributed in the paramagnetic lattice, impoverished of an electrical charge. It is shown that SGV stems from the presence of regions with different electrical charges in both samples.

• Periodical: Solid State Phenomena (Volume 190)
• Pages: 703-706
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.190.703
• Online since: June 2012
• Authors: D.M. Zashchirinskii, L.I. Koroleva, A.S. Morozov
• Keywords: Charge Ordering, Curie Temperature, Magnetic Two-Phase Ferromagnetic–Antiferromagnetic State, Magnetization, Manganite, Néel Temperature, Spontaneous Generation of Voltage

References

[1] T. Takahashi, O. Yamada, Phys. Chem. Solids 17 (1976) 161.

[2] A.D. Johnson, P I. Katz, J. Appl. Phys. 48 (1977) 73.

[3] Yu.N. Koval, A.L. Molin, Fiz. Met. Metalloved. 49 (1980) 1099.

[4] V.V. Kokorin, V.A. Chernenko, Fiz. Met. Metalloved. 60 (1985) 285.

[5] E M Levin, V K Pecharsky, K A Gschneidner, Phys. Rev. B 63 (2001) 4110.

[6] M. Zou, H. Tang, D.L. Schlagel, T.A. Lograsso, K.A. Gschneidner, V.K. Pecharsky, J. Appl. Phys. 99 (2006) 304.

[7] M. Zou, J.A. Sampaio, V.K. Pecharsky, K.A. Gschneidner, Phys. Rev. B 80 (2009) 2403.

[8] V.V. Runov, D. Yu. Chernyshov, A.I. Kurbakov, M.K. Runova, V.A. Trunov, A.I. Okorokov, J. Exp. and Theor. Phys. 91 (2000) 1017.

DOI: 10.1134/1.1334992

[9] C. Martin, A. Maignan, M. Hervieu, B. Raveau, Phys. Rev. B 60 (1999) 12191.

[10] V.V. Runov, H. Glattli, G.V. Kopitsa, A.I. Okorokov, M.K. Runova, JETP Lett. 69 (1999) 353.

DOI: 10.1134/1.568021

[11] V. Runov, H. Glattli, G. Kopitsa, A. Okorokov, M. Runova, Physica B 276-278(2000) 795.

DOI: 10.1016/s0921-4526(99)01324-1

[12] A.I. Abramovich, L.I. Koroleva, A.V. Michurin, J. Exp. and Theor. Phys. 95 (2002) 917.

[13] L.I. Koroleva, Magnetic Semiconductors, Phys. Dept. of MSU, Moscow, (2003).

[14] E.L. Nagaev Colossal Magnetoresistance and Phase Separation in Magnetic Semiconductors, Imperial College Press, London, (2002).