Increase in magnetoresistivity in Ba_2CoS_3 via Zn~(2+) /Co~(2+) substitution

摘要

We report an increase of negative magnetoresistivity from 1.7% to 9% in the Ba_2Co_(0.5)Zn_(0.5)S_3 series (0 ≤ x ≤ 0.5), derived from Zn~(2+) /Co~(2+) substitution in Ba_2CoS_3; Zn~(2+) substitution destroys the one-dimensional antiferromagnetic ordering typical of Ba_2CoS_3, in favour of a paramagnetic behaviour, and considerably increases the value of the resistivity, and to the best of our knowledge Ba_2Co_(0.5)Zn_(0.5)S_3 shows the most negative magnetoresistivity among the one-dimensional sulfides (MR ～ 9%).rnBa_2CoS_3 shows a one-dimensional structure, in which corner-linked COS_4 tetrahedra form chains along the c axis.