Magnetic excitations in a low dimentional quasi-1D spin-one chain: PbCd2Ni6Te3O18

Recently one-dimensional (1D) spin-chain systems has attracted considerable attention due to possibility of Haldane formation for an integer spin system. The compounds PbCd2Ni6Te3O18 (M=Cd and Mn) having quasi-1D chains of Ni2+ (S=1) and Mn2+ (S=5/2) in their crystal structure exhibit remarkably interesting magnetic properties. The susceptibility reveals an antiferromagnetic ordering at 25.7 K for M = Cd and 86.0 K for M=Mn. Further, the heat capacity measurements also support the AFM magnetic ground state in both the compounds. Interestingly the susceptibility of M=Cd exhibits a broad maximum above TN indicating the presence of short range magnetic interactions. Our inelastic neutron scattering study on M=Mn on MARI reveals two well defined dispersive magnetic excitations below 20 meV at 5 K. To compare the magnetic exchange strength between Ni-Ni in PbCd2Ni6Te3O18 (M=Cd and Mn) compounds), we proposed to investigate magnetic excitations in M=Cd using the MERLIN spectrometer.