Zhang Zeyu, You Lu, Du Juan, Wang Junling, Jin Zuanming, Ma Guohong, Leng Yuxin
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.
Department of Physics, Shanghai University, Shanghai, 200444, China.
Sci Rep. 2018 Feb 19;8(1):3258. doi: 10.1038/s41598-018-21655-9.
The interplay among ferroelectric, magnetic and elastic degrees of freedom in multiferroics is the key issues in condensed matters, which has been widely investigated by various methods. Here, using ultrafast two-color pump-probe spectroscopy, the picosecond electron-phonon and spin-lattice coupling process in Dysprosium doped-BiFeO (BDFO) films on SrTiO (STO) substrate have been investigated systematically. The Dy-doping induced structural transition and magnetic enhancement in BDFO is observed by ultrafast electron-phonon and spin-lattice interaction, respectively. The elastic anomalies in BDFO films are revealed by the photo-induced coherent acoustic phonon. With increasing the Dy doping ratio, the frequencies of the acoustic phonon in the films are modulated, and the phonon transmission coefficient between films and substrate is found to approach unity gradually. The ultrafast observation of the tunability of the ferroelectric, magnetic and the elastic properties in the morphotropic phase boundary of rare-earth doped BFO films provides new insights into the integration of BFO in next-generation high frequency electro-magnetic and electroacoustic devices.
多铁性材料中铁电、磁和弹性自由度之间的相互作用是凝聚态物理中的关键问题，已通过各种方法进行了广泛研究。在此，利用超快双色泵浦-探测光谱，系统研究了在SrTiO（STO）衬底上的镝掺杂铋铁氧体（BDFO）薄膜中的皮秒级电子-声子和自旋-晶格耦合过程。通过超快电子-声子和自旋-晶格相互作用，分别观察到了BDFO中镝掺杂引起的结构转变和磁增强。光诱导相干声子揭示了BDFO薄膜中的弹性异常。随着镝掺杂比例的增加，薄膜中声子的频率受到调制，并且发现薄膜与衬底之间的声子传输系数逐渐接近1。对稀土掺杂BFO薄膜在准同型相界中铁电、磁和弹性性质可调性的超快观测，为BFO在下一代高频电磁和电声器件中的集成提供了新的见解。
