Chiral Physical Properties, Chiral Space and Chiral Magnetism

Katsuya Inoue

 Chirality is commonly found in nature from particle physics to molecular chemistry. It is characterized by a reflection asymmetry that we are most familiar with in terms of our left hand being the mirror opposite of our right hand. When this kind of handedness appears in the structure of atoms or molecules in a solid, it affects the way that the magnetic moments of unpaired electrons organize themselves through the Dzyaloshinskii-Moriya (DM) interactions. In a symmetric structure, these interactions cancel out, but in a chiral lattice they do not. The DM interactions stabilize a screwlike helical arrangement of the magnetic moments. The result is a helical magnetic arrangement with a winding period of several tens or hundreds of nanometers, which is much longer than the lattice constant. Therefore, even though the chiral properties depend on the symmetry of the lattice, they can be understood and manipulated at the mesoscopic level, independently of the structural details.

The research objectives can be listed below.
  1. Establish material design and method to prepare new chiral magnets.
  2. Quantification between structural chirality and magnetic chirality
  3. Find out new specific properties coming from macro-scale spin phase order.
  4. Establish way to new spintronics devices.

Design of Multifunctional Metal-Nitroxide Complexes Undergoing Magnetic Anomalies

Katsuya Inoue

 The current scientific interests of Dr. Kseniya Maryunina are in the field of molecular magnets and investigation of the new opportunities in design of heterospin systems with nitroxides exhibiting different magnetic anomalies. The most important research projects are focused on coordination compounds based on copper(II) complexes with nitroxide radicals that are of special interest for detailed studies of various thermally, pressure, or light induced phase transitions that accompanied by spin-crossover-like phenomenon. During structural rearrangements the elongated Jahn?Teller axis in Cu(II) coordination units flips, that caused by significant changes in the energy of exchange coupling between the odd electrons of Cu(II) and nitroxide groups and provokes magnetic anomalies in the χT(T) or μeff(T) dependences which are similar to the classical spin transitions. The long term goal is investigation and comparison of both chemical and physical influence on characteristics of heterospin systems based on nitroxide radicals and transition metal ions and establishment of the design rules of creation novel spin-crossover-like metal-nitroxide complexes with predictable and controllable functional properties

Keywords: molecular magnets, spin chemistry, nitroxide radicals, magneto-structural correlations, solid solutions, isotope effect, polymorphic transitions


研究拠点形成事業(Core-to-Core) A. 先端拠点形成型(日本学術振興会)「スピンキラリティを軸にした先端材料コンソーシアム」(代表:井上克也)(2015-2019)

A-STEP 実証タイプ(科学技術振興機構)「超高密度記録に資する分子誘電メモリデバイスの改良と実証研究」(代表:西原禎文)(2018-2019)