Magnetic structure oC

Neutron-diffraction measurements have been carried out to determine the nature of the magnetic ordering in (Formula presented)(Formula presented)C. (Formula presented)(Formula presented)C exhibits superconductivity below 11 K and magnetic ordering below 1.5 K. The magnetic structure is incommensurate and consists of ferromagnetic (110) planes of Tm moments aligned along the c axis with the magnitude of the moments modulated sinusoidally along the (110) direction, the modulation wave vector having a magnitude of 0.241 A(Formula presented). The magnetic structure as well as the modulation direction exhibited by (Formula presented)(Formula presented)C is different from that of other R(Formula presented)(Formula presented)C (R=Gd-Er) compounds. The modulated state formed by the Tm moments allows the superconductivity to coexist with the magnetic ordering below (Formula presented).