Oxygen isotope effect on the superconductivity and stripe phase in La 1.6−x Nd 0.4 Sr x CuO 4
Abstract
The oxygen isotope effect on the superconductivity, stripe phase and structure transition is systematically investigated in La
1.6−x
Nd
0.4
Sr
x
CuO
4
with static stripe phase. Substitution of
16
O by
18
O leads to a decrease in superconducting transition temperature T
C
, while enhances the temperature of the structural transition from low-temperature-orthorhombic (LTO) phase to low-temperature-tetragonal (LTT) phase. Compared to the Nd free sample, a larger isotope effect on
T
C
is observed in La
1.6−x
Nd
0.4
Sr
x
CuO
4
. These results indicate that the distortion of CuO
2
plane suppresses the superconductivity, giving a direct evidence for the competing of stripe phase and superconductivity because the distortion of CuO
2
plane enhances the stripe phase.