Single crystal growth of Mn4Nb2O9 and its structure-magnetic coupling

A single crystal of Mn4Nb2O9 of about 8 mm in diameter and 30 mm in length was successfully grown by a newly designed one-step method based on the optical floating zone technique. Clear Laue spots and sharp XRD Bragg reflections attest the good crystal quality. The antiferromagnetic phase transition at T-N = 108.4 K of the Mn4Nb2O9 single crystal was observed along the c axis, which contrasts with Co4Nb2O9 belonging to the same structural family. Structural changes with a-axis shrinkage and c-axis expansion at T-N demonstrate a significant and anisotropic magnetostriction effect.