NMR study of infinite-layer compound Sr1−xLaxCuO2

Михалев, К. Н.; Kumagai, K.; Furukawa, Yuji; Бобровский, В. И.; D’yachkova, T. V.; Kad'irova, N.; Gerashenko, A.

doi:10.1016/s0921-4534(98)00288-3

Cited by 11 publications

(9 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is significantly smaller than that observed in the HDHTSC (16 MHz to 40 MHz [36]). However it is comparable to the upper estimate of the nuclear quadrupole frequency in superconducting samples of the EDHTSC, Nd 2-x Ce x CuO 4 (< 2 MHz [15]), and it is consistent with the estimates from two previous studies on Sr 1-x La x CuO 2 with x>=0.07 (<~3 MHz [16,18]).…”

Section: Results and Analysissupporting

confidence: 89%

“…Previous reports of NMR measurements on the infinite layer EDHTSC, Sr 1-x La x CuO 2 [16,17,18], have shown that the Cu spin lattice relaxation rate in the normal state increases with decreasing temperature, although the absolute values of the Cu spin lattice relaxation rate are different in these studies. This compound has the advantage that it does not contain magnetic rare earth ions that can affect the NMR data.…”

Section: Introductionmentioning

confidence: 78%

See 1 more Smart Citation

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1
Williams
¹
,
Dupree
²
,
Howes
³

et al. 2002
Phys. Rev. B
27
2
14
0
View full text Add to dashboard Cite

We report the results from a thermopower and a Cu nuclear magnetic resonance (NMR) study of the infinite CuO 2 layer electron doped high temperature superconducting cuprate (HTSC), Sr 0.9 La 0.1 CuO 2 . We find that the temperature dependence of the thermopower, S(T), is different from that observed in the hole doped HTSC. In particular, we find that dS(T)/dT is positive above ~120 K. However, we show that S(T) can still be described by the same model developed for the hole doped HTSC and hence S(T) is not anomalous and does not imply phonon mediated pairing as has previously been suggested. The Cu NMR data reveal a Knight shift and spin lattice relaxation rate below T c that are inconsistent with isotropic s-wave pairing. The Cu spin lattice relaxation rate in the normal state, however, is Curie-Weiss like and is comparable to that of the optimally and overdoped hole doped HTSC, La 2-x Sr x CuO 4 .The magnitude of the Knight shift indicates that the density of states at the Fermi level is anomalously small when compared with the hole doped HTSC with the same T c , indicating thatthe HTSC. We find no evidence of the normal state pseudogap that is observed in the hole doped HTSC and which was recently reported to exist in the electron doped HTSC, Nd 1.85 Ce 0.15 CuO 4 , from infrared reflectance measurements. PACS: 74.72.-h 74.25.Nf 74.25.Hawould appear to suggest a different superconducting pairing mechanism when compared with the HDHTSC. Furthermore, a thermopower study has concluded that the superconducting pairing mechanism is phonon mediated [25].In this paper we report the results from a Cu NMR study and a variable temperature thermopower study of the infinite layer EDHTSC, Sr 0.9 La 0.1 CuO 2 . Dense high quality samples of this compound have recently been synthesized with a high superconducting transition temperature of 43 K [23]. We compare our results with those from previous measurements on the HDHTSC. Experimental DetailsThe sample for this study was prepared using the high-pressure technique described elsewhere [23,26]. The dc magnetization measurements were made using a SQUID magnetometer, where the remnant field was ±0.1 mT. The data were not corrected for demagnetizing effects. Variable temperature thermopower measurements were made using the standard temperature differential technique. X-ray diffraction measurements confirmed that the sample was single phase.Cu NMR measurements were made on both unorientated powder and c-axis aligned powder samples in resin. Powder spectra were obtained at fields of 5.6 T, 8.45 T, and 14.1 T, point-by-point using the π/2-τ-π-τ Hahn pulse sequence, where π/2 was between 2 µs and 10 µs and τ was between 30 µs and 40 µs. The second half of the echo was Fourier transformed and then integrated, or summed, to obtain the intensity at each frequency. As the probes used to obtain the spectra had a Cu background, data was not taken near this frequency. The temperature dependence of the shift and the 63 Cu spin lattice relaxation time, 1 63 63 / 1 is plotted in figure 5 wher...

show abstract

Section: Results and Analysissupporting

confidence: 89%

Section: Introductionmentioning

confidence: 78%

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1
Williams
¹
,
Dupree
²
,
Howes
³

et al. 2002
Phys. Rev. B
27
2
14
0
View full text Add to dashboard Cite

show abstract

“…Thus, we identify material chemistry parameters, the hole contents at planar Cu and O, that are largely temperature independent, yet determine the superfluid density at low temperatures. This finding stimulates the use of these orbital hole contents, calculated from NMR literature data161819202122232425262728293031323334353637383940414243444546474849, to draw a three-dimensional cuprate phase diagram that encompasses all cuprate families and has the superconducting domes ordered according to the maximum T c . We argue that such a phase diagram might be very useful in discussing the complex properties of the cuprates.…”

mentioning

confidence: 80%

Perspective on the phase diagram of cuprate high-temperature superconductors

et al. 2016

View full text Add to dashboard Cite

Universal scaling laws can guide the understanding of new phenomena, and for cuprate high-temperature superconductivity the influential Uemura relation showed, early on, that the maximum critical temperature of superconductivity correlates with the density of the superfluid measured at low temperatures. Here we show that the charge content of the bonding orbitals of copper and oxygen in the ubiquitous CuO2 plane, measured with nuclear magnetic resonance, reproduces this scaling. The charge transfer of the nominal copper hole to planar oxygen sets the maximum critical temperature. A three-dimensional phase diagram in terms of the charge content at copper as well as oxygen is introduced, which has the different cuprate families sorted with respect to their maximum critical temperature. We suggest that the critical temperature could be raised substantially if one were able to synthesize materials that lead to an increased planar oxygen hole content at the expense of that of planar copper.

show abstract

“…Since Sr 1-x La x CuO 2 contains no magnetic cations other than the Cu ion, the interplay between the magnetism and superconductivity has been extensively studied by such probing methods as nuclear magnetic resonance (NMR), muon spin resonance (µSR), and angle-resolved photoemission spectroscopy (ARPES). [10][11][12] To extract generic features of electron-doped high-T c cuprates, a systematic study of Sr 1-x La x CuO 2 is highly required.…”

mentioning

confidence: 99%

“…between the magnetism and superconductivity has been extensively studied by such probing methods as nuclear magnetic resonance (NMR), muon spin resonance (µSR), and angle-resolved photoemission spectroscopy (ARPES). [10][11][12] To extract generic features of electron-doped high-T c cuprates, a systematic study of Sr 1-x La x CuO 2 is highly required. However, this is challenging due to the difficulty in preparing high-quality samples, and thus the pairing symmetry is still under debate.…”

mentioning

confidence: 99%

OptimalT_cfor Electron-Doped Cuprate Realized under High Pressure

et al. 2013

View full text Add to dashboard Cite

The race to obtain a higher critical temperature (T c ) in the superconducting cuprates has been virtually suspended since it was optimized under high pressure in a hole-doped trilayer cuprate. We report the anomalous increase in T c under high pressure for the electron-doped infinite-layer cuprate Sr 0.9 La 0.1 CuO 2 in the vicinity of the antiferromagnetic critical point. By the application of a pressure of 15 GPa, T c increases to 45 K, which is the highest temperature among the electron-doped cuprates and ensures unconventional superconductivity. We describe the electronic phase diagram of Sr 1−x La x CuO 2 to discuss the relation between the antiferromagnetic order and superconductivity.KEYWORDS: high-T c cuprates, electron-doped cuprates, high pressure, infinite-layered structure Electron-hole symmetry/asymmetry has been conceived as one of the most important features of the high-T c cuprates. 1-3) The asymmetry is manifested in generic phase diagrams as a function of the doping level. The antiferromagnetic (AF) phase exists in a low and narrow doping range for the hole-doped cuprates, whereas that for the electron-doped cuprates remains up to a high doping level, allowing the emergence of superconductivity. However, the electronic phase diagram for the electron-doped cuprates relies only on results for the family of R 2-x Ce x CuO 4 (R: rare-earth metal) 4,5) , which leaves uncertainty in discussions on the generic electron-hole asymmetry. For an other electron-doped cuprate, infinite-layer Sr 1-x R x CuO 2 with the optimum T c of 43 K, while the superconductivity has been investigated as a function of x, [6][7][8][9] the relation between the AF order and the superconductivity remains unclear. Since Sr 1-x La x CuO 2 contains no magnetic cations other than the Cu ion, the interplay

show abstract

NMR study of infinite-layer compound Sr1−xLaxCuO2

Cited by 11 publications

References 24 publications

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1
Williams
¹
,
Dupree
²
,
Howes
³

et al. 2002
Phys. Rev. B
27
2
14
0
View full text Add to dashboard Cite

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1
Williams
¹
,
Dupree
²
,
Howes
³

et al. 2002
Phys. Rev. B
27
2
14
0
View full text Add to dashboard Cite

Perspective on the phase diagram of cuprate high-temperature superconductors

OptimalT_cfor Electron-Doped Cuprate Realized under High Pressure

Contact Info

Product

Resources

About

NMR study of infinite-layer compound Sr1−xLaxCuO2

Cited by 11 publications

References 24 publications

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1Williams1, Dupree2, Howes3 et al. 2002Phys. Rev. B272140View full textAdd to dashboardCite

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1Williams1, Dupree2, Howes3 et al. 2002Phys. Rev. B272140View full textAdd to dashboardCite

Perspective on the phase diagram of cuprate high-temperature superconductors

OptimalTcfor Electron-Doped Cuprate Realized under High Pressure

Contact Info

Product

Resources

About

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1
Williams
¹
,
Dupree
²
,
Howes
³

et al. 2002
Phys. Rev. B
27
2
14
0
View full text Add to dashboard Cite

Gap anisotropy, spin fluctuations, and normal-state properties of the electron-doped superconductorSr0.9La0.1
Williams
¹
,
Dupree
²
,
Howes
³

et al. 2002
Phys. Rev. B
27
2
14
0
View full text Add to dashboard Cite

OptimalT_cfor Electron-Doped Cuprate Realized under High Pressure