Metal–insulator transition induced by oxygen isotope exchange in the magnetoresistive perovskite manganites

Babushkina, N. A.; Belova, Lyubov; Gorbenko, O. Yu.; Kaul, A. R.; Bosak, A.; Ozhogin, V. I.; Кugel, K. I.

doi:10.1038/34380

Cited by 152 publications

(177 citation statements)

References 13 publications

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“…In tight-binding approximation, the bandwith W is proportional to 1/m * . Therefore, the enhancement of m * leads to a decrease of W. The slight increase in high-temperature resistivity for 18 18 O. The isotope exponent (α S ) is about -0.8.…”

Section: Experiments Detailsmentioning

confidence: 99%

“…An electronic microbalancer (Mitteler-Telado XL26) with 1 µg precision was used for sample weighting. The 18 O sample has 70%(±1%) 18 O and 30%(±1%) 16 O. To make sure the isotope exchange effect, back-exchange of 18 O sample by 16 O was carried out in the same way and the weight change recorded showed a complete backexchange.…”

Section: Experiments Detailsmentioning

confidence: 99%

“…Therefore, its resistivity may jump several orders when the Co 3+ ion abruptly change from IS to LS state. Figure 2 shows the magnetic susceptibilities of assynthesized sample, 16 18 O should arise from the phonon behavior. It suggests that there must be strong electron-phonon coupling in this system since large change in resistivity and magnetic susceptibility is induced.…”

Section: Experiments Detailsmentioning

confidence: 99%

“…It suggests that there must be strong electron-phonon coupling in this system since large change in resistivity and magnetic susceptibility is induced. The substitution of 16 O by 18 O reduces the frequency of phonon, and then enhances the effective mass of electron (m * ) through the strong electronphonon coupling. In tight-binding approximation, the bandwith W is proportional to 1/m * .…”

Section: Experiments Detailsmentioning

confidence: 99%

See 3 more Smart Citations

Oxygen isotope effect on the spin-state transition in(Pr0.7Sm0.3)0.7Ca0.3CoO3

Wang

Luo

et al. 2006

Phys. Rev. B

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Oxygen isotope substitution is performed in the perovskite cobalt oxide (Pr0.7Sm0.3)0.7Ca0.3CoO3 which shows a sharp spin state transition from the intermediate spin (IS) state to the low spin (LS) state at a certain temperature. The transition temperature of the spin state up-shifts with the substitution of 16 O by 18 O from the resistivity and magnetic susceptibility measurements. The up-shift value is 6.8 K and an oxygen isotope exponent (αS) is about -0.8. The large oxygen isotope effect indicates strong electron-phonon coupling in this material. The substitution of 16 O by 18 O leads to a decrease in the frequency of phonon and an increase in the effective mass of electron (m * ), so that the bandwidth W is decreased and the energy difference between the different spin states is increased. This is the reason why the Ts is shifted to high temperature with oxygen isotopic exchange.

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Section: Experiments Detailsmentioning

confidence: 99%

Section: Experiments Detailsmentioning

confidence: 99%

Section: Experiments Detailsmentioning

confidence: 99%

Section: Experiments Detailsmentioning

confidence: 99%

See 2 more Smart Citations

Oxygen isotope effect on the spin-state transition in(Pr0.7Sm0.3)0.7Ca0.3CoO3

Wang

Luo

et al. 2006

Phys. Rev. B

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“…Recent observations in several classes of "strongly correlated" materials (high-temperature superconductors, "colossal magnetoresistance" manganites, and alkalimetal doped C 60 ) of large isotope effects on electronic properties, including electron effective mass 4-8 and superconducting, 4-9 magnetic, [10][11][12][13] and charge ordering [14][15][16][17] transition temperatures pose a fundamental challenge to this understanding and call for a theory that goes beyond ME. Some authors 6,7,10,12 have attempted to relate their experimental data to formulas derived for the case of a "polaron": a single electron interacting with lattice deformation.…”

Section: Introductionmentioning

confidence: 99%

Dynamical mean-field theory of electron-phonon interactions in correlated systems: Application to isotope effects on electronic properties

Deppeler

Millis

2002

Phys. Rev. B

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We use a recently developed formalism (combining an adiabatic expansion and dynamical meanfield theory) to obtain expressions for isotope effects on electronic properties in correlated systems. As an example we calculate the isotope effect on electron effective mass for the Holstein model as a function of electron-phonon interaction strength and doping. Our systematic expansion generates diagrams neglected in previous studies, which turn out to give the dominant contributions. The isotope effect is small unless the system is near a lattice instability. We compare this to experiment. 71.38.Cn, 71.27.+a

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Effects of thermal imidization on mechanical properties of poly(amide‐co‐imide)/multiwalled carbon nanotube composite films

Lee

Choi

Kim

et al. 2010

J of Applied Polymer Sci

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In this study, experimental and numerical studies were performed to investigate the relationship among the functionalization method, weight fraction of MWCNTs, thermal imidization cycle, and mechanical properties of various PAI/MWCNT composite films. Poly(amide-co-imide)/multiwalled carbon nanotube composite films were prepared by solution mixing and film casting. The effects of chemical functionalization and weight fraction of multiwalled carbon nanotubes on thermal imidization and mechanical properties were investigated through experimental and numerical studies. The time needed to achieve sufficient thermal imidization was reduced with increasing multiwalled carbon nanotube content when compared with that of a pure poly(amide-co-imide) film because multiwalled carbon nanotubes have a higher thermal conductivity than pure poly(amide-co-imide) resin. Mechanical properties of pure poly(amide-coimide) and poly(amide-co-imide)/multiwalled carbon nanotube composite films were increased with increasing imidization time and were improved significantly in the case of the composite film filled with hydrogen peroxide treated multiwalled carbon nanotubes. Both the tensile strength and strain to failure of the multiwalled carbon nanotube filled poly(amide-co-imide) film were increased substantially because multiwalled carbon nanotube dispersion was improved and covalent bonding was formed between multiwalled carbon nanotubes and poly(amideco-imide) molecules.

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Metal–insulator transition induced by oxygen isotope exchange in the magnetoresistive perovskite manganites

Cited by 152 publications

References 13 publications

Oxygen isotope effect on the spin-state transition in(Pr0.7Sm0.3)0.7Ca0.3CoO3

Oxygen isotope effect on the spin-state transition in(Pr0.7Sm0.3)0.7Ca0.3CoO3

Dynamical mean-field theory of electron-phonon interactions in correlated systems: Application to isotope effects on electronic properties

Effects of thermal imidization on mechanical properties of poly(amide‐co‐imide)/multiwalled carbon nanotube composite films

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