Comparison of pressure, magnetic field and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites
The pressure, magnetic field and excess manganese effects on transport and magnetoresistance effect (MRE) have been studied in both the epitaxial films and bulk ceramics of manganites (La₀.₇Ca₀.₃)₁₋xMn₁₊xO₃₋y (x = 0–0.2). A comparison of electrical behavior in both kinds of samples of similar com...
Збережено в:
Дата: | 2006 |
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Автори: | , , , , , , , , , , , |
Формат: | Стаття |
Мова: | English |
Опубліковано: |
Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України
2006
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Назва видання: | Физика низких температур |
Теми: | |
Онлайн доступ: | http://dspace.nbuv.gov.ua/handle/123456789/120130 |
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Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
Цитувати: | Comparison of pressure, magnetic field and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites / V.I. Mikhaylov, V.P. Dyakonov, E.E. Zubov, A.V. Pashchenko, V.N. Varyukhin, V.A. Shtaba, A. Szewczyk, A. Abal’oshev, K. Piotrowski, K. Dyakonov, S.J. Lewandowski, H. Szymczak // Физика низких температур. — 2006. — Т. 32, № 2. — С. 190-200. — Бібліогр.: 43 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of UkraineРезюме: | The pressure, magnetic field and excess manganese effects on transport and magnetoresistance
effect (MRE) have been studied in both the epitaxial films and bulk ceramics of manganites
(La₀.₇Ca₀.₃)₁₋xMn₁₊xO₃₋y (x = 0–0.2). A comparison of electrical behavior in both kinds of samples
of similar composition at hydrostatic pressures of up to 1.8 GPa and in a magnetic fields of up
to 8 kOe has been performed. The pressure and magnetic field effects are shown to increase with
increasing manganese content. Experimental data show that the pressure and magnetic field effects
on temperatures of both metal–insulator transition (TMD) and MRE peak (TMR) are considerably
stronger in the films than in ceramics. The hydrostatic pressure increases TMD and TMR.
Magnetoresistance effect for both types of samples was shown to be favored by the pressure and
magnetic field in an opposite way. A direct correlation is established between TMD and conductivity
bandwidth as well as between MRE and concentration of charge carriers at applied pressure.
The differences in the values of pressure effect on resistance, MRE and TMD temperature in the
films and ceramics are connected with both granular structure of ceramics and the oxygen
nonstoichiometry in ceramic and film samples of the same content as well as with the film strain
induced by lattice mismatch between the film and the substrate. The origin of pressure–magnetic
field effects is analyzed in the framework of double exchange interaction and small polaron hopping,
and variable range hopping models. |
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