Neutron diffraction study of crystal and magnetic structure of (La0.7Ca0.3)1–xMn1+xO3 (x = 0, 0.1) systems

Bażela, W.; Dyakonov, V. P.; Pashchenko, V. P.; Penc, B.; Szymczak, H.; Hernández–Velasco, J.; Szytuła, A.

doi:10.1002/pssb.200301703

Cited by 8 publications

(1 citation statement)

References 5 publications

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“…A strong influence of manganese excess on magnetic properties and resonance has been established both in La-Ca manganites [24][25][26][27] and in self-doping manganites [28]. The main results of the cited references are as follows: using the NMR method it was shown that the manganese ions with ionization states both close to (3+) and (4+) and with intermediate valence result from the high-frequency electron exchange; FM-to-canted spin state transition in clusters of multivalent Mn ions by magnetic and neutron measurements was observed; observation of FMR and spin-wave resonance in the films of manganites with manganese excess.…”

Section: Introductionmentioning

confidence: 99%

Comparison of pressure, magnetic-field, and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites

Mikhaylov

Zubov

Pashchenko

et al. 2006

Low Temperature Physics

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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 (La 0.7 Ca 0.3) 1-x Mn 1+x O 3-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 (T MD) and MRE peak (T MR) are considerably stronger in the films than in ceramics. The hydrostatic pressure increases T MD and T MR. 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 T MD 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 T MD 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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Section: Introductionmentioning

confidence: 99%

Comparison of pressure, magnetic-field, and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites

Mikhaylov

Zubov

Pashchenko

et al. 2006

Low Temperature Physics

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The influence of doping on the electronic structure of R1−xCaxBa2Cu3O6+d (R=Y, Eu) and (La0.7Ca0.3)1−xMn1+xO3

Szytuła

Starowicz

Penc

2003

Physica C: Superconductivity

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Structural and magnetic inhomogeneity and the NMR of Mn55 and La139 in the magnetoresistive ceramics La0.7Ba0.3−xSnxMnO3→La0.7−xBa0.3−xMnO3+0.5xLa2Sn2O7

Pashchenko¹,

Shemyakov²,

Savosta³

et al. 2003

Low Temperature Physics

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The effects of substitution of barium by tin on the phase composition, structural imperfection, and properties of lanthanum manganite perovskites La0.7Ba0.3−xSnxMnO3 (x=0, 0.1, 0.15, 0.2, 0.3) are established by comprehensive studies done by x-ray diffraction, resistive, and magnetic (including NMR on Mn55 and La139) methods. It is shown that the introduction of Sn leads to the formation of a pyrochloric phase La2Sn2O7, to an increase in the density of lattice defects of the manganese-enriched main lanthanum manganite phase, and to a substantial decrease of the magnetoresistive effect. The smearing of the metal–semiconductor phase transition temperature is explained by an increase in the inhomogeneity and imperfection of the perovskite structure. The low activation energy is confirmed by a high degree of inhomogeneity and imperfection of the crystal lattice of the samples studied. The broad, asymmetric NMR spectra of Mn55 and La139 attest to high-frequency electron exchange between Mn3+ and Mn4+ and nonequivalence of the environment of those ions and La3+ due both to heterovalent ions and to vacancies and clusters.

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Neutron diffraction study of crystal and magnetic structure of (La_0.7Ca_0.3)_1–xMn_1+xO₃ (x = 0, 0.1) systems

Cited by 8 publications

References 5 publications

Comparison of pressure, magnetic-field, and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites

Comparison of pressure, magnetic-field, and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites

The influence of doping on the electronic structure of R1−xCaxBa2Cu3O6+d (R=Y, Eu) and (La0.7Ca0.3)1−xMn1+xO3

Structural and magnetic inhomogeneity and the NMR of Mn55 and La139 in the magnetoresistive ceramics La0.7Ba0.3−xSnxMnO3→La0.7−xBa0.3−xMnO3+0.5xLa2Sn2O7

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