Magnetodielectric properties of the square cupola antiferromagnet Ba(TiO)Cu-4(PO4)(4)

摘要

Magnetodielectric properties of the tetragonal magnetic insulator Ba(TiO)Cu-4(PO4)(4) consisting of asymmetric Cu4O12 square cupolas have been investigated in a magnetic field along the [001] axis (B-[001]), where a metamagnetic transition occurs at B-c||[001] similar to 12 T and 1.4 K. Clear anomalies associated with the transition to the high-field phase are observed in dielectric constants both along the [100] (epsilon([100])) and [001] (epsilon([001])) axes. It is found that the B dependence of epsilon([001]) and epsilon([100]) across B-c||[001] is anisotropic: epsilon([001]) decreases while epsilon([100]) increases. The origin of this anisotropic magnetodielectric response is discussed.