铁磁-d波超导结中的粗糙界面散射和自旋反转效应对隧道谱的影响

EFFECTS OF INTERFACE ROUGHNESS AND SPIN-FLIP ON TUNNELSPECTRUM IN FERROMAGNET-d-WAVE SUPERCONDUCTOR JUNCTIONS

考虑到铁磁层中的自旋极化效应、以及界面的粗糙散射和自旋反转效应 ,利用推广了的Blonder Tinkham Klap wijk理论模型 ,计算铁磁 d波超导结中的自旋极化隧道谱 .研究表明 1)自旋反转效应能使零偏压电导峰变得尖锐 ;2 )粗糙的界面散射除了能压低零偏压电导峰的高度 ,还能使零偏压凹陷处感应出一中心峰 .结果能定性地解释最近的两篇关于La2 3 Ba1 3 MnO3 DyBa2 Cu3O7与La2 3 Ba1 3 MnO3 YBa2 Cu3O7-δ结中的实验报道 .

Taking into account the spin-polarized effect, rough interface scattering and spin-flip effects, we calculate, within Blonder-Tinkham-Klapwijk Scattering formalism, the spin-polarized tunnel spectrum in the ferromagnet-d-wave superconductor junctions. It is shown that, (1) the conductance exhibits a sharp peak at zero-bias with the increase in spin-flip scattering; (2) the interface roughness can induce a small central peak in the zero-bias conductance dip and decrease the height of the zero-bias conductance peak. The calculated results can account for the tunnel spectrum observed experimentally in La2/3Ba1/3MnO3/DyBa2Cu3O7 and La2/3Ba1/3MnO3/YBa2Cu3O7-delta junctions.