Peculiarities of magnetic, galvanomagnetic, elastic, and magnetoelastic properties of Eu0.55Sr0.45MnO3

Magnetic, elastic, magnetoelastic, transport, and magnetotransport properties of the Eu(0.55)Sr(0.45)MnO3 ceramics have been studied. A break was detected in the temperature dependence of electrical resistivity rho(T) near the temperature of the magnetic phase transformation (41 K), with the materia...

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Veröffentlicht in:Fizika tverdogo tela 2004-09, Vol.46 (9), p.1711-1716
Hauptverfasser: Abramovich, A. I., Gorbenko, O. Yu, Kaul, A. R., Koroleva, L. I., Michurin, A. V.
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Sprache:eng
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Zusammenfassung:Magnetic, elastic, magnetoelastic, transport, and magnetotransport properties of the Eu(0.55)Sr(0.45)MnO3 ceramics have been studied. A break was detected in the temperature dependence of electrical resistivity rho(T) near the temperature of the magnetic phase transformation (41 K), with the material remaining an insulator down to the lowest measurement temperature reached (rho = 10 exp 6 omega cm at 4.2 K). In the interval T in the range 4.2 to 50 K, the isotherms of the magnetization, volume magnetostriction, and rho were observed to undergo jumps at the critical field H(sub C1), which decreases with increasing T. For T in the range 50 - 120 K, the jumps in the above curves persist, but the pattern of the curves changes and HC1 grows with increasing T. The magnetoresistance Delta-rho/rho = (rho(sub H) - rho(sub H=0))/rho(sub H) is positive for H less than H(sub C1) and passes through a maximum at 41 K, where Delra-rho/rho = 6 percent. For H greater than H(sub C1), the magnetoresistance is negative, passes through a minimum near 41 K, and reaches a colossal value of 3 x 10 exp 5 percent at H = 45 kOe. The volume magnetostriction is negative and attains a giant value of 4.5 x 10 exp -4 at H = 45 kOe. The observed properties are assigned to the existence of three phases in Eu(0.55)Sr(0.45)MnO3, namely, a ferromagnetic (FM) phase, in which carriers are concentrated because of the gain in s-d exchange energy, and two antiferromagnetic (AFM) phases of the A and CE types. Their fractional volumes at low temperatures were estimated to be as follows: approximately 3 percent of the sample volume is occupied by the FM phase; approximately 67 percent, by the CE-type AFM phase; and approximately 30 percent, by the A-type AFM phase.
ISSN:1063-7834
0367-3294
1090-6460
DOI:10.1134/1.1799191