Magnetization and magnetodielectric effect in Cr3+-doped Ca3Co2-xCrxO6 compounds

Abstract

In one dimensional Ca3Co2O6, the magnetic frustration could result in partially disordered antiferromagnetic state. The Ca3Co2O6 thus presents spin freezing and slow relaxation at low temperature. In this investigation, magnetic Cr3+-dopants were chosen to substitute the Co3+ cations and a series of Ca3Co2-xCrxO6 ceramics were synthesized. Their magnetoelectric properties were characterized. The results manifest that the introduced Cr3+ cations situate in the CoO6 octahedral centers and they could increase the lattice volume slightly. The antiferromagnetic coupling between Cr3+ and the adjacent Co3+ could reduce the frustration. The doped-Ca3Co2-xCrxO6 compounds display a slower magnetic dynamic behavior. The Cr3+ substitution also has great impact on the dielectric properties of Ca3Co2O6. The slower response of the freezing spin in Cr3+ doped-Ca3Co2O6 makes the dielectric anomaly (anomaly Ⅰ) around the freezing temperature weakens with increasing Cr3+. Additionally, the introduced Cr3+ dopant not only increases the dielectric permittivity but also decreases the dielectric loss greatly. Cr3+ cation is a good candidate for improving the dielectric properties of Ca3Co2O6. Magnetodielectric measurement reflects the effectiveness of magnetic field on manipulating the electric dipole of Ca3Co2O6. For spin frustrated materials, electric measurement is proved to be an effective method on characterizing the subtle variation of the magnetic structure.