New Dielectric Anomaly in DyMn2−xGaxO5

We have studied the effect of Ga3+ substitution into the Mn3+ site in DyMn2O5 on its multiferroic charateristics. Crystallographic structural, thermal, dielectric and magnetic properties are measured and discussed in terms of the dilution of magnetic Mn3+ ions. Replacement of Mn3+ with Ga3+ changes the compound into a disordered multiferroic system and the colossal magnetodielectric effect observed in DyMn2O5 diappears quickly below x 0.1 in DyMn2−xGaxO5. However, as the content of Ga is increased above x 0.1, a new type of ferroelectric transition, identified by a peak in dielectric constant, can be obtained from the slowly varying dielectric background. Moreover, a remarkable enhancement of the dielectric constant at the ferroelectric transition temperature is continued, even up to the solubility limit of Ga (x 0.2). This observation suggests one possible channel for ferroelectricity in disordered multiferroic systems. We have studied the effect of Ga3+ substitution into the Mn3+ site in DyMn2O5 on its multiferroic charateristics. Crystallographic structural, thermal, dielectric and magnetic properties are measured and discussed in terms of the dilution of magnetic Mn3+ ions. Replacement of Mn3+ with Ga3+ changes the compound into a disordered multiferroic system and the colossal magnetodielectric effect observed in DyMn2O5 diappears quickly below x 0.1 in DyMn2−xGaxO5. However, as the content of Ga is increased above x 0.1, a new type of ferroelectric transition, identified by a peak in dielectric constant, can be obtained from the slowly varying dielectric background. Moreover, a remarkable enhancement of the dielectric constant at the ferroelectric transition temperature is continued, even up to the solubility limit of Ga (x 0.2). This observation suggests one possible channel for ferroelectricity in disordered multiferroic systems. KCI Citation Count: 1