A tetragonal zircon-type DyCrO${}_4$ with space group $I4{}_1/\mathit{amd}$ was prepared at ambient pressure. By quenching this zircon phase from 6.0 GPa and 720 K, another tetragonal scheelite-type DyCrO${}_4$ was obtained with the reduction of lattice symmetry to $I4{}_1/a$. Both phases contain spatially separated CrO${}_4$ tetrahedra with rare Cr${}^{5+}$ state and Cr-O-Dy-O-Cr spin interaction chains. In the zircon phase, significantly different Cr-O-Dy bond angles were found along different lattice axes, giving rise to ferromagnetic and antiferromagnetic interactions around 23 and 21 K, respectively. Due to magnetic frustration caused by the competitive ferromagnetic and antiferromagnetic interactions, a field-induced metamagnetic transition took place at a small field about 0.15 T. In the scheelite phase, antiferromagnetic ordering occurred below 24 K. Similar to the zircon phase, field-induced metamagnetism was also observed in the scheelite-type DyCrO${}_4$, but at a higher field of about 3.0 T. Possible orbital ordering was discussed in the high-pressure scheelite phase.

• Received 4 November 2010

DOI:https://doi.org/10.1103/PhysRevB.83.024416