脉冲激光沉积温度及氧压对Bi_2Sr_2Co_2O_y热电薄膜晶体结构与电输运性能的影响

摘要

We fabricate Bi_2Sr_2Co_2O_y,films on C-Al_2O_3 by pulsed laser deposition and investigate the effects of substrate temperature and oxygen pressure on the crystal stucture and the transport properties of the films.The resulting single phase c-axis C-Al_2O_3 films obtained under the optimal condition have a room temperature resistivity of about 2.9 mΩ/cm and a seebeck coefficient of 110μV/K, leading to a larger power factor than that of the single crystal.In addition,a negative magnetroresistance of 40%at 2 K and 9 T is observed in the films.%利用脉冲激光沉积技术在c-Al_2O_3单晶基片上制备了Bi_2Sr_2CO_2O_y热电薄膜并研究了沉积温度和氧压对薄膜晶体结构及电输运性能的影响.在最佳沉积条件下制备的单相、c轴取向的Bi_2Sr_2Co_2O_y薄膜的室温电阻率ρ和塞贝克系数S分别为2.9 mΩ/cm和110μV/K,其功率因子S~/ρ好于在单晶样品上得到的值.此外,该薄膜在低温下表现出较强的负磁阻效应,在2 K,9 T时达到了40%.