Magnetization and neutron-diffraction studies of magnetic properties of single-crystal DyMn2Ge2.

Abstract

Magnetic properties of single-crystal ${\mathrm{DyMn}}_{2}$${\mathrm{Ge}}_{2}$ have been studied by magnetization measurement in high fields up to 150 kOe and by neutron diffraction. Four magnetically ordered phases have been observed. In low magnetic fields parallel to the [001] direction, collinear antiferromagnetism is observed in the temperature range from 37.5 to 431 K with the Mn moments ferromagnetically coupled on the (001) layers, and with antiferromagnetic coupling between the adjacent (001) Mn layers. Below 33 K, there is a collinear ferrimagnetic structure with the Dy and Mn moments antiparallel to each other along the c axis. A new magnetic phase is observed in the temperature range between 33 and 37.5 K, where its magnetic structure is not uniquely determined but the averaged moments at the Dy and the Mn atoms are evaluated to be about 6${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$ and 1${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$, respectively. Another new magnetic phase is observed in high magnetic fields along the [001] directions below 65 K. The magnetic structure of this phase, which has been deduced from the magnetization measurement, is a canted ferrimagnetic structure, with the Dy moments oriented along the c axis, and the Mn moments canted away from the c axis.