Investigation into the Magnetoelectric Effect and Magnetic Properties of Iron-doped Cobalt Molybdate

Abstract

The plausibility of revealing linear magnetoelectric coupling is investigated in the cobalt molybdate (Co2Mo3O8). Recently, Wang et al.[Scientific Reports. 2015;Vol. 5:Article 12268] showed that iron molybdate(Fe2Mo3O8) can be induced into a ferrimagnetic state from a nominal antiferromagnetic state via application of a magnetic field. As such, it may be possible that cobalt molybdate exhibits a similar effect intrinsically or with addition of iron dopant. Single crystals of the hexagonal molybdate (Co(1-x)Fe(x))2Mo3O8 (x=0, 0.25, 0.5, 0.75, 1) were synthesized via chemical vapour transport. The magnetic properties were investigated along the polar axis and in the basal plane. Despite doping with iron, no metamagnetic phase transition was present in (Co(1-x)Fe(x))2Mo3O8 (x=0.25, 0.5, 0.75). Low field measurements of the susceptibility reveal the presence of an anisotropic ferromagnetic-like moment, which is suppressed at moderate fields. This is believed to be a product of an exchange-bias-like phenomena, which is not fully understood. The magnetocapacitance was measured along the c-axis for x=(0.25, 0.5). Co1.5Fe0.5Mo3O8 exhibits the conventional magnetodielectric effect, with a proportionality constant of 5.1(0.3) x10^(-14) Oe^(-2) at 40K, while the capacitance of Co1Fe1Mo3O8 shows linear dependency on H, with slope -6.99(0.07) x10^(-9) Oe^(-1) at 49K.