PbMn(SO4)2: A new chiral antiferromagnet

PbMn(SO4)2 has been synthesized in an evacuated quartz tube. The nuclear and magnetic crystal structures have been determined using powder X-ray and neutron diffraction. This material crystallizes in the enantiomorphic space group pair P41212(♯92) and P43212(♯96), forming a double-helical arrangement of Pb2+ and Mn2+ cations. The Mn2+O6 octahedra are distorted. Each 3d5 Mn2+ has four nearest-neighbors and four next-nearest-neighbors adopting a frustrating arrangement. The compound orders antiferromagnetically at 5.5 K. Field dependent specific heat and magnetization measurements show that TN is suppressed to 3.3 K when μ0H=9 T.