Light-Induced Magnetic Switching as a Trigger for Phase Transitions in Molecular Materials

有了这个奖项，化学系的化学结构，动力学机制B计划资助了一个由Mykhailo Shatruk和Nar S教授领导的合作研究小组。Dalal博士与佛罗里达州立大学化学和生物化学系的研究人员合作，研究光响应分子，这种分子可以将热、压力或光照射的作用转化为材料磁性和结构特性的实质性变化。 这一设计原理的成功实施可能会导致新的铁电体和导体，可以通过光的作用来驱动。利用Shatruk和Dalal团队在磁性和光磁材料，铁电材料和有机导体的合成和表征方面的专业知识，该团队旨在创造可用于电子设备或光激活开关的新型多功能材料。该项目将积极让研究生和本科生参与实验室研究，包括来自物理科学代表性不足的群体的学生。该研究小组计划继续他们的本科生暑期学校的磁性，第一次在2012年和2014年夏天组织，与下一个学校定于2016年夏天。该项目的目标是光响应分子的合成和表征，能够翻译温度，压力，或光诱导的系统的磁状态的变化转化为实质性的结构变化，这将因此在材料中触发另一种类型的相变。Shatruk/Dalal团队将探索在分子水平上将光致磁双稳性与分子基材料中的长程金属-绝缘体转变和铁电有序（磁性或电性）耦合的方法。特别是，该团队将研究具有自旋交叉（SCO）行为的Fe（II）络合物，该行为源于Fe（II）离子的抗磁性低自旋（LS）和顺磁性高自旋（HS）状态之间的温度或光诱导转变。将调用光诱导LS到HS的转变，以便通过光激发实现诸如铁电性和导电性的性质。SCO与导电性共存的材料将提供一个平台来测试与SCO相关的协调原子位移对有机子结构导电性的影响，并有可能通过化学压缩实现光致超导。 另一个推力旨在探索光致磁开关，类似于SCO，在无金属的有机系统中，磁状态的变化是由于顺磁性自由基和反磁性自由基二聚体之间的相互转换。对这种无金属体系的研究可以在分子磁学领域开辟一个新的领域，这将与目前对过渡金属络合物的研究相平行。

With this award, the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division is funding a collaborative research team led by Professors Mykhailo Shatruk and Nar S. Dalal of the Department of Chemistry and Biochemistry at Florida State University to investigate photoresponsive molecules that can translate the action of heat, pressure, or light irradiation into substantial changes into changes in the magnetic and structural properties of materials. The successful implementation of this design principle could potentially lead to new ferroelectrics and conductors that could be actuated by the action of light. Leveraging the expertise of the Shatruk and Dalal groups in the synthesis and characterization of magnetic and photomagnetic materials, ferroelectric materials, and organic conductors, the team aims to create novel multifunctional materials that can be employed in electronic devices or light-activated switches. The project will actively involve graduate and undergraduate students in laboratory research, including students from groups underrepresented in physical sciences. The research team plans to continue their Undergraduate Summer Schools on Magnetism, first organized in Summers of 2012 and 2014, with the next school scheduled for Summer 2016.This project targets the synthesis and characterization of photoresponsive molecules capable of translating temperature-, pressure-, or light-induced changes in the magnetic state of the system into substantial structural changes, which consequently would trigger another type of phase transition in the material. The Shatruk/Dalal team will explore approaches to couple the photoinduced magnetic bistability at the molecular level to long-range metal-insulator transitions and ferroic orderings (magnetic or electric) in molecule-based materials. In particular, the team will study Fe(II) complexes with spin crossover (SCO) behavior, which stems from the temperature or light-induced transition between diamagnetic low-spin (LS) and paramagnetic high-spin (HS) states of the Fe(II) ion. The photoinduced LS to HS transitions will be invoked in order to achieve properties such as ferroelectricity and conductivity via photoexcitation. Materials in which SCO coexists with conductivity will provide a platform to test the effects of concerted atomic displacements associated with SCO on the conductivity of the organic substructure, with the potential to achieve photoinduced superconductivity via chemical compression. Another thrust aims to explore photoinduced magnetic switching, akin to SCO, in metal-free organic systems, where the change in the magnetic state is due to interconversions between paramagnetic radicals and diamagnetic dimers of radicals. The study of such metal-free systems could open up a new area in the molecular magnetism field that would parallel the studies currently performed on transition metal complexes.