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Peculiarities of the magnetic, galvanomagnetic, elastic, and magnetoelastic properties of Sm1-xSrxMnO3 manganitesстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Abramovich A.I., Koroleva L.I., Michurin A.V.
- Журнал: Journal of Experimental and Theoretical Physics
- Том: 95
- Номер: 5
- Год издания: 2002
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 917
- Последняя страница: 926
- DOI: 10.1134/1.1528684
- Аннотация: Manganites of the Sm1 - xSrxMnO3 system (x = 0.33, 0.4, and 0.45) possess giant negative values of the magnetoresistance Deltarho/rho and the volume magnetostriction omega near the Curie temperature T-C. In the compound with x = 0.33, the isotherms of Deltarho/rho, omega, and magnetization sigma exhibit smooth variation and do not reach saturation up to maximum magnetic field strengths (120 kOe) studied (according to the neutron diffraction data, this substance comprises a ferromagnetic (FM) matrix with distributed clusters of a layered antiferromagnetic (AFM) structure of the A type). In the compounds with x = 0.4 and 0.45 containing, besides the FM matrix and A-type AFM phase, a charge-ordered AFM phase of the CE type (thermally stable to higher temperatures as compared to the A-type AFM and the FM phases), the same isotherms measured at T greater than or equal to T-C show a jumplike increase in the interval of field strengths between H-c1 and H-c2 and then reach saturation. In the interval H-c1 < H < H-c2, the sigma, omega, and Deltarho/rho values exhibit a metastable behavior. At temperatures above T-C, the anisotropic magnetostriction changes sign, which is indicative of rearrangements in the crystal structure. The giant values of omega and Deltarho/rho observed at T greater than or equal to T-C for all compounds, together with excess (relative to the linear) thermal expansion and a maximum on the rho(T) curve, are explained by the phenomenon of electron phase separation caused by a strong s-d exchange. The giant values of magnetoresistance and volume magnetostriction (with omega reaching similar to10(-3)) are attributed to an increase in the volume of the FM phase induced by the applied magnetic field. In the compound with x = 0.33, this increase proceeds smoothly as the FM phase grows through the FM layers in the A-type AFM phase. In the compounds with x = 0.4 and 0.45, the FM phase volume increases at the expense of the charge-ordered CE-type AFM structure (in which spins of the neighboring manganese ions possess an AFM order). The jumps observed on the sigma(H) curves, whereby the magnetization sigma reaches similar to70% of the value at T = 1.5 K, are indicative of a threshold character of the charge-ordered phase transition to the FM state. Thus, the giant values of omega and Deltarho/rho are inherent in the FM state, appearing as a result of the magnetic-field-induced transition of the charge-ordered phase to the FM state, rather than being caused by melting of this phase. (C) 2002 MAIK "Nauka / Interperiodica".
- Добавил в систему: Абрамович Анна Ивановна