Abstract :
The temperature dependent (30–300 K) Doppler broadening of the positron annihilated γ-radiation measurement has been investigated on single crystalline Bi2Sr2CaCu2O8+δ (Bi-2212) high Tc superconducting samples along two different crystallographic orientations. It has been observed that throughout the temperature range the electron momentum distribution has a larger value along the crystallographic c-axis than in the a–b plane. The temperature dependent Doppler broadened positron annihilation γ-radiation lineshape analysis shows a step like increase of S-parameter at the temperature region 92–116 K.
