Fundamentals and perspectives of ultrafast photoferroic recording

The ability to switch ferroics (ferro-, ferri-, antiferromagnets, ferroelectrics, multiferroics) between two stable bit states is one of the keystones of modern data storage technology. Due to many new ideas, originating from fundamental research during the last 50 years, this technology has developed in a breath-taking fashion. Finding a conceptually new way to control ferroic state of a medium with the lowest possible production of heat and at the fastest possible timescale is a new challenge in fundamental condensed matter research. Controlling ferroic state of media by light is a promising approach to this problem. Photomagnetism and photoferroelectricity have long been intriguing and the development of femtosecond laser sources made this approach even more appealing. Laser pulse is the shortest stimulus in contemporary experimental physics of condensed matter. While commercial lasers are able to produce pulses with duration of the order of tens of femtosecond, advanced laser sources can generate intense pulses of light even at the sub-femtosecond timescale. Seeking understanding a response of magnetically-ordered media to ultrashort excitation led to foundation of new research field of ultrafast magnetism, discoveries of all-optical magnetic switching in various metallic and dielectric materials. Despite obvious analogies between magnetically-ordered and ferroelectric materials, the issue of the ultrafast switching of the order parameter in the latter class of ferroics has been given very little attention. This raises an obvious question about the possibility of optical switching of the spontaneous polarization in ferroelectrics and the prospects of information recording in ferroelectrics by means of light. Here we briefly review the main findings of earlier studies of optical control of spontaneous magnetization and polarization, highlight recent developments of ultrafast magnetism and magnetic recording with femtosecond laser pulses, and discuss a new field of ultrafast ferroelectricity. Analyzing the literature, we derive the most promising strategies for optical recording in ferroic media and speculate about applicability of the strategy proven to be efficient in magnetically-ordered media, to ferroelectrics and multiferroics. (C) 2020 The Author(s). Published by Elsevier B.V.