Fe_3O_4薄膜的电输运及光诱导特性研究

Electrical transport and photo-induced properties in Fe_3O_4 film

用脉冲激光沉积法在(111)Si衬底上成功制备了高度择优取向的Fe3O4薄膜.电阻-温度关系表明Fe3O4薄膜的Verwey转变(TV)约在122K,低温段(T<TV)输运特征满足Mott变程跳跃模型,高温段(T>TV)为小极化子输运.激光作用下的光电导实验发现,在整个温区表现为光致电阻率减小,而且低温段的电阻变化率比高温段要大很多.分析认为Fe3O4薄膜的光致电阻率变化主要与激光激发t2g电子的转移有关.

Highly oriented Fe3O4 film was fabricated on Si （ 111 ） substrate by pulsed laser deposition. The resistivity-temperature curve shows that the Verwey transition point is about 122 K,and the electrical transport mechanism agrees with Mott varial-range hopping model and the small polaron model for temperatures below TV and above TV,repectively. The laser irradiation results in the decrease of the resistivity of the film in the whole temperature range were measured, which is attributed to the intersite transitions of Fe 3d t2g electrons.