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Ferroelectricity in a one-dimensional organic quantum magnet

2010; Nature Portfolio; Volume: 6; Issue: 3 Linguagem: Inglês

10.1038/nphys1503

1745-2481

Fumitaka Kagawa, Sachio Horiuchi, Masashi Tokunaga, J. Fujioka, Yoshinori Tokura,

Multiferroics and related materials

Measurements of the magnetic-field-dependent polarization of a one-dimensional organic quantum magnet suggest its ferroelectric behaviour is mediated by a spin–Peierls instability. Such behaviour could provide a promising new approach to the design of spin-driven ferroelectrics. In magnetically controllable ferroelectrics1,2,3, electric polarization is induced by charge redistribution or lattice distortions that occur to minimize the energy associated with both the magnetic order and interaction of spins with an applied magnetic field. Conventional approaches to designing materials that exploit such spin-mediated behaviour have focused mainly on developing the cycloidal spin order4,5, and thereby producing ferroelectric behaviour through the so-called antisymmetric Dzyaloshinskii–Moriya interaction6,7,8. However, engineering such spin structures is challenging. Here we suggest a different approach. Direct measurements of magnetic-field-dependent variations in the polarization of the one-dimensional organic quantum magnet, tetrathiafulvalene-p-bromanil, suggest a spin–Peierls instability has an important role in its response. Our results imply that one-dimensional quantum magnets, such as organic charge-transfer complexes, could be promising candidates in the development of magnetically controllable ferroelectric materials.