Antisite disorder driven cluster glass state and colossal magnetoresistance in MnSb2Se4

Antisite disorder plays a significant role in determining the ground state of a magnetic material. The ternary
chalcogenide material MnSb2Se4 with ∼26% antisite disorder between Mn and Sb sites is known to be an
antiferromagnet (TN = 22.5 K) and a type-II mulitferroic. In this paper, we report the effect of increased antisite
disorder (∼40%) on the magnetic and electrical transport properties of this compound. Magnetic susceptibility
and heat-capacity measurements indicate the absence of long-range magnetic ordering. Furthermore, AC susceptibility
measurements unfold its nonequilibrium magnetic dynamics at low temperatures. Data analysis with
various dynamic scaling models, namely, power law, Arrhenius law, and Vogel-Fulcher confirm a cluster glass
state. Moreover, the presence of magnetic memory effect and magnetic relaxation reveal the nonequilibrium
dynamics of the system through many metastable states. In addition, a negative colossal magnetoresistance is
observed below the freezing temperature due to competing ferromagnetic and antiferromagnetic interactions
induced by increased antisite disorder. These results indicate that MnSb2Se4 is a new addition to a very small
group of chalcogenides which show negative colossal magnetoresistance.