Raman study on the effects of sintering temperature on the Jc(H) performance of MgB2 superconductor

Abstract

The influence of sintering temperature on the critical transition temperature Tc and critical current density Jc for the MgB2 superconductor was investigated systematically with the observation of Raman scattering measurement and flux pinning force Fp analysis. The enhanced E2g mode in Raman spectra with increasing in situ sintering temperature shows gradual strengthening of the electron-phonon coupling in MgB2, which means that the crystals become more harmonic after higher temperature sintering. However, the crystal harmonicity is degraded for samples sintered at even higher temperature due to Mg deficiency. A possible explanation for the Jc(H) performance, which is in accordance with the Raman spectroscopy observation and Fp analysis, is the cooperation between the electron-phonon coupling in the E2g mode and the flux pinning centers, mainly originating from the lattice distortion due to the different sintering temperatures.