Chiral Magnetism: Coupling Static and Dynamic Chirality

Abstract

The synthesis, structure, magnetic properties and magnetic structure of two molecular chiral magnets and one inorganic chiral magnet are presented. In magnetic crystals belonging to the Sohncke group, which includes the chiral group, the chiral non-collinear spin structure is achieved through Dzyaloshinsky-Moriya interactions in addition to the usual exchange spin interactions and dipole-dipole spin interactions. Experimentally, a chiral helical magnetic (CHM) structure is observed as the ground state in most of this category of uniaxial chiral magnets as a non-collinear spin structure. CHM structure transforms into a chiral spin soliton (CS) magnetic structure in a magnetic field. The (CS) magnetic structure forms a chiral spin soliton lattice (CSL) magnetic structure when the nearest neighbor magnetic interaction is ferromagnetic. Since the CHM and CSL magnetic structures are topologically protected, they are not affected by defects and are therefore extremely stable. A series of studies have revealed that the chiral magnetic structure is perfectly coupled to the non-symmetric crystal structure. It was also found that the CHM and CSL magnetic structures are macroscopic spin-phase coherent states.

Recognition in the Domain of Molecular Chirality: From Noncovalent Interactions to Separation of Enantiomers

“…30,1020−1023 Absolute asymmetric synthesis has been reported to be also promoted by physical chiral forces, such as circularly polarized light and chiral magnetic fields. 35,239,914,1024,1025 Very recently, Sakamoto et al performed chiral symmetry breaking from a racemate using optical vortices with orbital angular momentum and a helical wavefront. 1026 This methodology of asymmetric transformation originates by the combination of enantioselective crystal nucleation by irradiation with optical vortices and crystallization-induced dynamic optical resolution of conglomerate crystals.…”

“…In this method, in the absence of any external asymmetric source, a chiral compound having a chiral center is obtained from a prochiral substrate, and a dynamic preferential crystallization (section ), along with the racemization of the new chiral center, is performed continuously, producing a crystal of the product with high enantiomeric purity. In the last few years, this approach has been applied to diverse reaction systems. ,− Absolute asymmetric synthesis has been reported to be also promoted by physical chiral forces, such as circularly polarized light and chiral magnetic fields. ,,,, Very recently, Sakamoto et al performed chiral symmetry breaking from a racemate using optical vortices with orbital angular momentum and a helical wavefront . This methodology of asymmetric transformation originates by the combination of enantioselective crystal nucleation by irradiation with optical vortices and crystallization-induced dynamic optical resolution of conglomerate crystals.…”

Dark discrete breather modes in monoaxial chiral helimagnet with easy-plane anisotropy

“…Noncollinear spin textures in chiral helimagnets and their concomitant fundamental excitations have aroused research interest as technologically relevant objects for spintronic applications [71][72][73] . Unfortunately, nonlinear breather excitations lie outside the mainstream of these investigations and the number of relevant works is very limited 75,76 .…”

Nonlinear Optical and Magnetic Properties of FeII-SCN-HgII Isomers: Centrosymmetric Layers and Chiral Networks

“…Polymorphism and isomerism in coordination polymers are phenomena observed in crystalline materials that can form two or more solid-state phases with identical chemical formulas but different molecular arrangements generated by the rotation around a single bond for polymorphs or breaking any bond for isomers. , These two phenomena can be initiated both at the synthetic stage, using specific types of reagents, solvents, and synthesis conditions (e.g., pH, temperature, pressure, crystallization methods, etc. ), , and the post-synthetic chemical and physical modification of materials. , The most vivid example of isomerism is the formation of diverse-dimensionality structures depending on experimental conditions for [{HC­(3-Phpz) 3 }­Ag]­(BF 4 ) (pz = pyrazolyl) and [Ag­(2-bpt)]­(NO 3 ) (2-bpt = 3,5-bis­(2-pyridyl)-4-amino-1,2,4-triazole), which can form zero-dimensional (1D) rings and one-dimensional (1D) helical chains. , In this context, polymorphism and isomerism are extremely important effects for the crystal engineering of new crystalline phases and probing correlations between physicochemical properties and structural features. , Moreover, it is worth emphasizing that magnetic polymorphs and isomers are underrepresented among two- (2D) and three-dimensional (3D) functional magnetic coordination polymers, which have gained considerable attention in the last three decades. , Notably, research on high-dimensional coordination polymers has resulted in the rapid emergence of innovative research fields that combine attractive magnetic behaviors such as spin bistability, − long-range magnetic coupling, − photomagnetism, − and slow magnetic relaxation − with other functionalities such as conductivity, − luminescence, − sorption, − and nonlinear optical (NLO) activity. − …”