Influencing magnetism of quasi 1D spin-chain compound Ca3CoMnO6 by Ni substitution at Co site

Earlier studies show that the multiferroicity in the spin-chain compound Ca₃CoMnO₆ critically depends upon the Co/Mn ratio. In order to establish the role of Co and Mn in controlling the multiferroic properties, we intend to disturb this ratio to find out its implications on the physical properties. The present study is aimed at studying modification of the properties of Ca₃CoMnO₆ by partial substitution of Ni for Co. The combined results of structural, magnetic and dielectric studies show interesting changes as a function of Ni substitution. There is a drastic difference in M(H) behavior at T < T_N for Ca₃Co_1−xNi_xMnO₆ (x = 0.0, 0.2) compounds. The magnetodielectric properties are also largely different for x = 0.0 and 0.2 samples. The MDE for x = 0.0 is negative with ∼7% variation, whereas for x = 0.2 it is positive with about 1% variation over the temperature range of measurement. Therefore, Ni substitution clearly alters the magnetic structure resulting in the change of magnetic space group, thus influencing the overall magnetic properties.