Enhancement of Electronic Anomalies in Iron-Substituted La_2-xSr_xCu_1-yFe_yO₄ around x=0.22

Abstract

Since the early stage of the research on high-T c superconductivity, much attention has been paid to the physics in the overdoped regime, e.g., the disappearance of the so-called pseudogap at a hole concentration per Cu, p, of ∼ 0.19, 1 a topological change of the Fermi surface, 2 a possible phase separation into superconducting (SC) and normal-state regions. 3,4 In particular, around x = 0.22 in the overdoped regime of La 2−x Sr x CuO 4 (LSCO), significant anomalies have been observed thus far: a slight depression of the SC transition temperature T c , 5, 6 the development of the Cu-spin correlation at low temperatures, 7 the enhancement of lattice instability by the application of a magnetic field, 8 and an anomalous insensitivity of the thermal conductivity to a magnetic field. 9 These are suggestive of a possible development of the stripe correlations of holes and spins 10 around x = 0.22, because these are analogous to those observed around x = 1/8 where the stripe correlations are much developed.Recently, Fujita et al. have revealed from their elastic neutron-scattering experiment that incommensurate magnetic peaks around (1/2, 1/2) in the reciprocal lattice unit are enhanced through the partial substitution of Fe for Cu in LSCO around p = 1/8. 11 Moreover, incommensurate elastic nuclear peaks around (0, 2) in the reciprocal lattice unit are observed in Fe-substituted samples around p = 1/8, while they are unobservable in an Fe-free sample of x = 0.12. 12 It is well known that superconductivity is strongly suppressed through Fe substitution in the whole SC regime. 13, 14 Therefore, Fujita et al. 11 have suggested that Fe substitution is effective for the stabilization of the charge-spin stripe order around p = 1/8.In this study, we have investigated Fe-substitution effects on electronic properties around x = 0.22 in the overdoped regime of LSCO by measuring the electrical resistivity ρ and the magnetic susceptibility χ.Polycrystalline samples of 1 % Fe-substituted La 2−x Sr x Cu 1−y Fe y O 4 with y = 0.01 were prepared by the ordinary solid-state reaction method. The details have been reported in our previous paper. 5 All the samples were checked by powder X-ray diffraction analysis to be of

An x-ray scattering study of the structural phase transition in La2−xSrxCu0.99Fe0.01O4(x= 0.20)

“…Finally, we compare our result with previous investigation on the critical exponent β [6,7,11,12] in figure 9. It is interesting to note that the values for 2β increase with the doping and following a trend line well described by an exponential function.…”

“…The Fe-doped La 2−x Sr x CuO 4 system is attracting much attention due to the dual roles of Fe 3+ as the charge impurity (Fe 3+ substituting for Cu 2+ ) and the magnetic impurity (Fe 3+ has a large magnetic moment S = 5/2). The transport measurements indicate that the electronic anomalies around x = 0.22 in the overdoped region were enhanced by Fe substitution, which might be related to the development of stripe correlations [11]. To better understand the changes in the electronic properties induced by Fe doping mentioned above, detailed information about the structural properties of the Fe-doped LSCO in the overdoped regime is necessary.…”

Distinct Fe-induced magnetic states in the underdoped and overdoped regimes of La2−xSrxCu<

“…[36] All the samples were checked by the powder x-ray diffraction to be of the single phase. Electrical-resistivity measurements revealed the good quality of the samples.…”

Distinct Fe-induced magnetic states in the underdoped and overdoped regimes of La2-xSrxCu1-yFeyO4 revealed by muon spin relaxation

“…Polycrystalline samples of LSCFO with x = 0.06 -0.235 and y = 0.005, 0.01 were prepared by the ordinal solid-state reaction method. [36] All the samples were checked by the powder x-ray diffraction to be of the single phase. Electrical-resistivity measurements revealed the good quality of the samples.…”