⁵⁵Mn NMR investigation of the correlation between antiferromagnetism and ferroelectricity in TbMn₂O₅

The correlation between antiferromagnetism and ferroelectricity in magnetoelectric multiferroic TbMn₂O₅ has been investigated by zero-field ⁵⁵Mn NMR. Antiferromagnetic transition near 40 K is found to be first order. When an external field up to 7 T is applied along the easy a axis, a dramatic change in the signal intensity is observed which is hysteretic in nature. Such effects are absent for H along the b and c axes. The observed field-induced signal enhancement is attributed to antiferromagnetic domain walls which are strongly coupled to ferroelectric domain walls. Experimental data suggest that this may be related to the field-induced ferromagnetic ordering of the Tb ion.