Towards observation of magnetic excitation in organic conductor

Kawamura, Seiko   ; Nakajima, Kenji  ; Inamura, Yasuhiro  ; Kikuchi, Tatsuya  ; Taniguchi, Hiromi*

There is no report of application of inelastic neutron scattering on organic conductors until today because of the tiny size and amount of their crystals. Recently, it was reported that synthesis of huge single crystal (a few mm class) of -(BEDT-TTF)ICl had been succeeded. The system exhibits an antiferromagnetic order below 22 K. We performed a neutron scattering experiment on this system as the first step toward observation of the magnetic excitation in the organic conductor. The measurement was carried out using a cold-neutron disk-chopper spectrometer AMATERAS installed in J-PARC. About 230 pieces of the single crystals (1.5 g) was aligned to mount onto a sample holder. Bragg diffractions from the crystal were indexed along the [100] direction, which is perpendicular to the two-dimensional (2D) plane. Magnetic Bragg peak was not observed in this direction because of rapid damping of the magnetic form factor.