New type of magnetic structure in the R 2 T 2 X group: Tb 2 Pd 2 In.

Anisotropy of bulk magnetic properties and magnetic structure studies of a Tb2Pd2In single crystal by means of bulk magnetization methods and neutron diffraction techniques confirmed the antiferromagnetic order below the Neel temperature 29.5 K. The collinear magnetic structure of Tb magnetic moments aligned along the tetragonalc-axis is characterized by a propagation vectork= (1/4, 1/4, 1/2), yielding an equal-moment-size structure with alternating coupling between nearest as well as next-nearest Tb neighbors within the basal plane and antiferromagnetic coupling between thec-axis neighbors. In the context of magnetism of R2T2X compounds, where R stands for rare-earth or actinide element, such collinear structure with long-wavelength periodicity represents a new type of magnetic structure.