Multiferroicity in the spin-1/2 quantum matter of LiCu2O 2

Abstract

Multiferroicity in Li Cu2 O2 single crystals is studied using resonant soft x-ray magnetic scattering, hard x-ray diffraction, heat capacity, magnetic susceptibility, and electrical polarization. Two magnetic transitions are found at 24.6 K (T1) and 23.2 K (T2). Our data are consistent with a sinusoidal spin structure at T2 < T1 and with a helicoidal spin structure at T< T2, giving rise to ferroelectricity. Surprisingly, above T2, the correlation lengths of the spin structures increase as the temperature increases with dramatic changes of ∼42% occurring along the c axis. © 2008 American Institute of Physics.