https://doi.org/10.1007/s100510070076
Anelastic relaxation and 139La NQR in La2-xSrxCuO4 around the critical Sr content x = 0.02
1
Dipartimento di Fisica "A. Volta"and Unitá INFM di Pavia,
Via Bassi 6, 27100 Pavia, Italy
2
Dipartimento di Fisica, Universitá di Roma "La Sapienza"and Unitá
INFM, P.zale A. Moro 2, 00185 Roma, Italy
3
CNR, Area di Ricerca di Roma-Tor Vergata, Istituto di Acustica "O.M. Corbino"and Unitá INFM,
Via del Fosso del Cavaliere, 00133 Roma, Italy
Received:
18
May
2000
Revised:
11
July
2000
Published online: 15 November 2000
Anelastic relaxation and 139LaNQR relaxation rates in La2-xSrxCuO4 for Sr content around 2 and 3 percent are discussed in terms
of spin and lattice excitations and of the related
ordering processes.
It is argued how the phase diagram of La2-xSrxCuO4
at the boundary
between the antiferromagnetic
(AF) and the spin-glass phase (x= 0.02) could be more
complicate than previously
thought, with a transition to a quasi-long range ordered state at
K, as indicated by neutron scattering data.
On the other hand,
the 139LaNQR spectra are compatible with a transition to an AF phase
around
K, in agreement with the phase diagram
commonly accepted in literature.
In this case the peaks in NQR and anelastic
relaxation rates around 150 K and 80 K respectively in La1.98Sr0.02CuO4,
yield the first evidence of
freezing process involving simultaneously lattice and spin excitations,
possibly corresponding to motion of charged stripes.
PACS: 74.25.Dw – Superconductivity phase diagrams / 76.60.-k – Nuclear magnetic resonance and relaxation / 62.40.+i – Anelasticity, internal friction, stress relaxation, and mechanical resonances
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000