[seminar] Seminar FO, Grafe

[hbuljan at phy.hr]

Poštovani kolege,

idući utorak 22.06. seminar naslovljen "New NMR results in the
prototypical high temperature superconductors La2xSrxCuO4 and YBa2Cu3Oy"
održati će nam H-J. Grafe iz Dresdena (vidi sažetak). Predavanje će se
održati na Fizičkom odsjeku PMFa u predavaonici F201 s početkom u 14.15
sati. Posjeta Dr. Grafe odvija se u sklopu suradnje na SOLeNeMaR projektu
kolege M. Požeka.

Srdačan pozdrav
H. Buljan

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SEMINAR FIZIČKOG ODSJEKA
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Vrijeme:   utorak, 26. 6. 2012., 14:15 sati (točno)
Mjesto:    Fizički odsjek, Bijenička c. 32, predavaonica F201

New NMR results in the prototypical high
temperature superconductors La2xSrxCuO4 and YBa2Cu3Oy

      Hans-Joachim Grafe
Leibniz Institute for Solid State Research, Dresden Germany


Even after 25 years of intense research on the high temperature
superconducting cuprates it is still possible to either prove findings
which were not generally accepted, or even to find totally new results
which were not known before. In my talk, I will present new NMR results on
the prototypical HTSC compounds La2-xSrxCuO4 and YBa2Cu3Oy. In the first
compound, we could recently prove that the average low temperature
orthorhombic structure as determined by x-ray scattering is fully
compatible with its local structure determined by a local probe as NMR
[1]. In the second compound, we explored the highly underdoped regime
(y=6.35-6.6), and found a new NMR signal which proves the emergence of a
static order below a critical hole doping of p_c ~ 0.095 [2].
Surprisingly, the pseudogap as determined by the NMR spin lattice
relaxation appears only above this critical doping level. Our data
suggests that a possibly stripe-like static order competes with the
spin-pseudogap phase, whereby both are separated by a critical hole doping
p_c.

[1] S.-H. Baek, A. Erb, B. Büchner, and H.-J. Grafe, Phys. Rev. B 85,
184508 (2012)
[2] S.-H. Baek, T. Loew, V. Hinkov, C. T. Lin, B. Keimer, B. Büchner, and
H.-J. Grafe, to be published
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