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Sr
CuO
Wakimoto, Shuichi; Yamada, Kazuyoshi*; Tranquada, J. M.*; Frost, C. D.*; Swainson, I.*; Birgeneau, R. J.*
Physica C, 460-462(1), p.166 - 169, 2007/09
Times Cited Count：1 Percentile：7.1(Physics, Applied)Spin excitations of overdoped LaSrCuO (
) have been studied by neutron scattering utilizing triple-axis and time-of-flight spectrometers. Low-energy excitation spectra (
meV) for all of the superconducting samples show a maximum around 
meV with a maximum value of dynamic spin susceptibility 
that decreases linearly with 
as doping increases. The magnetic scattering cross section finally disappears at 
, coincident with the disappearance of bulk superconductivity. Time-of-flight measurements for 
and 
shows markedly suppressed magnetic scattering intensities at intermediate energies (20
80meV) in contrast to those of the stripe-ordered La
Ba
CuO. These facts imply a cooperative correlation between the dynamic incommensurate state and the superconductivity.
SrCuO with and without Zn impuritiesWakimoto, Shuichi; Birgeneau, R. J.*; Kagedan, A.*; Kim, H.-K.*; Swainson, I.*; Yamada, Kazuyoshi*; Zhang, H.*
Physical Review B, 72(6), p.064521_1 - 064521_9, 2005/08
Times Cited Count：27 Percentile：71.83(Materials Science, Multidisciplinary)The magnetic properties of the Zn-substituted overdoped high-
superconductor LaSrCuO (LSCO) have been studied by magnetization measurements and neutron scattering. Magnetization measurements reveal that for Zn-free samples with 
a Curie term is induced implying the existence of local paramagnetic moments. A comparison of the Curie behaviour between Zn-doped and Zn-free samples signifies a general competitive relationship between the superconductivity and the induced paramagnetic moment. Neutron scattering measurements show that Zn-substitution in overdoped LSCO anomalously enhances the inelastic magnetic scattering spectra around the 
position, peaking at 
meV. These facts are discussed on the basis of a "swiss-cheese" model of Zn-substituted systems as well as a microscopic phase separation scenario in the overdoped region indicated by muon-spin-relaxation measurements.
SrCuOWakimoto, Shuichi; Birgeneau, R. J.*; Frost, C. D.*; Kagedan, A.*; Kim, H.*; Swainson, I.*; Tranquada, J. M.*; Yamada, Kazuyoshi*; Zhang, H.*
no journal, ,
Spin excitations of LSCO in the overdoped regime has been studied by neutron scattering. Incommensurate excitations around 6 meV which are clearly observed in the sample decrease with as doping increases, and finally, become unobservable at coincidentally with the disappearance of bulk superconductivity. High-energy measurements performed at the MAPS spectrometer show remarkably weakened magnetic excitations of the overdoped samples also in the high energy region. These observations are apparently consistent with a microscopic phase separation of the overdoped samples into the superconducting and Fermi liquid phases based on muSR results. In contrast, magnetization measurements of overdoped LSCO with and without Zn impurities have revealed that the superconductivity vanishes in the overdoped regime as a result of a competition between the superconductivity and paramagnetism which is induced even in the Zn-free overdoped LSCO.
