The dimpling in the CuO2 planes of YBa2Cu3Ox (x=6.806-6.984, T=20-300 K) measured by yttrium EXAFS

نویسندگان

  • J. Röhler
  • K. Conder
چکیده

The dimpling of the CuO2 planes (spacing between the O2,3 and Cu2 layers) in YBa2Cu3Ox has been measured as a function of oxygen concentration and temperature by yttrium x-ray extended-fine-structure spectroscopy (EXAFS). The relative variations of the dimpling with doping (x = 6.806 − 6.984) and temperature (20300 K) are weak (within 0.05 Å), and arise mainly from displacements of the Cu2 atoms off the O2,3 plane towards Ba. The dimpling appears to be connected with the transition from the underdoped to the overdoped regimes at x = 6.95, and with a characteristic temperature in the normal state, T ∗ ≃ 150 K.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

LOCAL STRUCTURE STUDIES OF THE UNDERDOPED-OVERDOPED TRANSITION IN YBa2Cu3Ox Measurement of the yttrium x-ray absorption-fine-structure

We have measured the extended x-ray absorption-fine-structure (EXAFS) at the Y-K edge of YBa2Cu3Ox for x=6.801, 6.947, 6.968, 6.984 at T=20-300 K. The Y–Cu2 pairs vibrate harmonically but freeze out in the superconducting phase. The Y-O2,3 pairs exhibit strong anharmonicities with a singularity at Tc. With increasing oxygen concentration the Cu2 layer shifts along c towards the Ba layer. Optimu...

متن کامل

Phaseseparation in overdoped Y1−0.8Ca0−0.2Ba2Cu3O6.96−6.98

The dimpling in the CuO2 planes of overdoped Y1−yCayBa2Cu3 O6.96−6.98, (y = 0.02−0.2) has been measured by x-ray absorption-fine-structure spectroscopy (Y-K EXAFS). A step-like decrease around 12% Ca indicates a percolation threshold for distorted sites of 5 cells, and thus phase segregation. We conclude the charge carriers added by substitution of Y by Ca to be trapped at the Ca sites and thei...

متن کامل

Plane dimpling and Cu 4s hybridization in YBa2Cu3Ox

Oxygen doping dimples the CuO2 planes of YBa2Cu3O6.8−6.92 by displacing copper normal to the planes and further towards Ba. The correlated oxygen displacements, however, are constrained to the in-plane axes. This displacement pattern is discussed in terms of doping dependent Cu 4s–3d hybridizations.

متن کامل

خواص ترابردی و شبه گاف در ابررسانای NdBa2-xLax Cu3O7-δ

 Polycrystalline samples of NdBa2-xLaxCu3O7-δ with x=0, 0.05, 0.10, 0.15, 0.20, and 0.30 were made by standard solid state methods. The transport and superconducting properties have been studied by the resistivity measurements as a function of temperature and doping concentration. In order to measurements the hole concentration in CuO2 planes, the room temperature thermoelectric power was measu...

متن کامل

Stripe structure and Non-Homogeneity of the CuO2 Plane by Joint EXAFS and Diffraction

Local structure of the Cu02 plane in Bi2Sr2CaCu208+8 (Bi2212) superconductor has been solved by joint Cu K-edge extended X-ray absorption fine structure (EXAFS) and anomalous X-ray diffraction. The Cu-0 pair distribution function (PDF) has been measured by EXAFS and diffraction. The displacement of the Cu ions along the c-axis shows largest amplitude and anharmonic character. The results show f...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 1997