Electric-Field-Induced Charge-Transfer Phase Transition: A Promising Approach Toward Electrically Switchable Devices

Abstract

Much research has been directed toward the development of electrically switchable optical materials for applications in memory and display devices. Here we present experimental evidence for an electric-field-induced charge-transfer phase transition in two cyanometalate complexes: Rb(0.8)Mn[Fe(CN)(6)](0.93).1.62H(2)O and Co(3)[W(CN)(8)](2)(pyrimidine)(4).6H(2)O, involving changes in their magnetic, optical, and electronic properties as well. Application of an electric field above a threshold value and within the thermal hysteresis region leads to a transition from the high- to the low-temperature phase in these compounds. A model is proposed to explain the main observations on the basis of a para-ferroelectric transition. Our observations suggest that this new concept of electrical switching, based on materials exhibiting charge-transfer phase transitions with large thermal hysteresis loops, may open up doors for novel electro-optical devices.

Switching Magnetic Properties by a Mechanical Motion

“…However, by increasing the temperature, a drop in the magnetization is observed at temperatures where the thermal energy is enough to allow for a relaxation to the stable LS state [24]. Apart from temperature and light, chemical [25], electrical [26], or pressure [27] stimuli have also been used to induce a spin crossover. Several stimuli have been used to trigger magnetic properties changes [3] in three main areas: (i) changing the spin state of a transition metal in spin crossover (SCO) systems [4][5][6][7][8][9][10][11]; (ii) switching the exchange interaction between different spin carriers [12,13]; and (iii) switching single-molecule magnet (SMM) properties [14,15].…”

“…However, by increasing the temperature, a drop in the magnetization is observed at temperatures where the thermal energy is enough to allow for a relaxation to the stable LS state [24]. Apart from temperature and light, chemical [25], electrical [26], or pressure [27] stimuli have also been used to induce a spin crossover. Multi-metallic complexes such as Prussian-blue analogues have also attracted a wide interest as switchable systems due to the ability to switch the exchange interaction between different spin carriers connected by a bridging cyanide ligand.…”

Multifunctional Material: Bistable Metal–Cyanide Polymer of Rubidium Manganese Hexacyanoferrate

“…31,32 Cyano-bridged metal complexes are structurally flexible due to the phonon mode of the cyano ligands and can tolerate switching of their spin states with structural changes. For these reasons, our research has focused on cyano-bridged metal complexes.…”

Growth Dynamics of Photoinduced Phase Domain in Cyano-Complex Studied by Boundary Sensitive Raman Spectroscopy

“…Particularly, rubidium manganese hexacyanoferrate is an attractive material because of its fascinating multiple functionalities. For instance, a pressure--induced magnetic pole inversion [3], coexistence of ferroelectricity and ferromagnetism [4], electric field induced charge transfer phase transition [5], and reversible photoinduced phase transition at low temperature [6] have been reported. This material shows thermal phase transition from high temperature phase (HTP) to low temperature phase (LTP) at the phase transition tempera- * corresponding author; e-mail: asahara@issp.u-tokyo.ac.jp configuration.…”