Moment canting and domain effects in antiferromagnetic DyRh2Si2

A combined experimental and theoretical study of the layered antiferromagnetic compound DyRh2Si2 in the ThCr2Si2-type structure is presented. The heat capacity shows two transitions upon cooling: The first one at the Néel temperature TN = 55 K and a second one at TN2 = 12 K. Using magnetization measurements, we study the canting process of the Dy moments upon changing the temperature and can assign TN2 to the onset of the canting of the magnetic moments towards the [100] direction away from the c axis. Furthermore, we found that the field dependence of the magnetization is highly anisotropic and shows a two-step process for H || 001. We used a mean-field model to determine the crystalline electric field as well as the exchange interaction parameters. Our magnetization data together with the calculations reveal a moment orientation close to the [101] direction in the tetragonal structure at low temperatures and fields. Applying photoemission electron microscopy, we explore the (001) surface of the cleaved DyRh2Si2 single crystal and visualize Si- and Dy-terminated surfaces. Our results indicate that the Si-Rh-Si surface protects the deeper lying magnetically active Dy layers and is thus attractive for investigation of magnetic domains and their properties in the large family of LnT2Si2 materials.