The Institute for Functional Imaging of Materials and The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Mail Stop 6487, Oak Ridge, Tennessee 37831, USA.
Nat Commun. 2016 Dec 2;7:13290. doi: 10.1038/ncomms13290.
Polarization switching in ferroelectric and multiferroic materials underpins a broad range of current and emergent applications, ranging from random access memories to field-effect transistors, and tunnelling devices. Switching in these materials is exquisitely sensitive to local defects and microstructure on the nanometre scale, necessitating spatially resolved high-resolution studies of these phenomena. Classical piezoresponse force microscopy and spectroscopy, although providing necessary spatial resolution, are fundamentally limited in data acquisition rates and energy resolution. This limitation stems from their two-tiered measurement protocol that combines slow (∼1 s) switching and fast (∼10 kHz-1 MHz) detection waveforms. Here we develop an approach for rapid probing of ferroelectric switching using direct strain detection of material response to probe bias. This approach, facilitated by high-sensitivity electronics and adaptive filtering, enables spectroscopic imaging at a rate 3,504 times faster the current state of the art, achieving high-veracity imaging of polarization dynamics in complex microstructures.
铁电和多铁材料中的极化反转支撑着广泛的当前和新兴应用，从随机存取存储器到场效应晶体管和隧道器件。这些材料中的反转对纳米级的局部缺陷和微结构极其敏感，因此需要对这些现象进行空间分辨的高分辨率研究。尽管经典的压电力显微镜和光谱学提供了必要的空间分辨率，但它们在数据采集速率和能量分辨率方面存在根本限制。这种限制源于它们的双层测量协议，该协议结合了缓慢（∼1 s）的切换和快速（∼10 kHz-1 MHz）的检测波形。在这里，我们开发了一种使用材料对探针偏置的直接应变检测来快速探测铁电切换的方法。这种方法通过高灵敏度电子设备和自适应滤波来实现，能够以比当前最先进技术快 3504 倍的速率进行光谱成像，实现了复杂微结构中极化动力学的高真实性成像。
