Magnetic structure of Rare Earth Francisites [Cu3 RE(SeO3)2O2Cl] {RE: La, Nd, Dy}

Mineral francisite (BiCufr) is fascinating due to degenerate ground states and presence of competing ferromagnetic (FM) intralayer and antiferromagnetic (AFM) interlayer exchanges. Magnetic ground state of two oppositely directed neighboring FM layers can be flipped into same direction by magnetic field and is called metamagnetic transition (MMT). Rare earth (RE) based francisites (RECufr) are synthetic analogues of mineral francisites and developed when Bi is replaced by RE. The RE francisites are curious due to 3d(Cu)-4f(RE) interaction and manifestation occurs in the form of spin reorientation transition (SRT). We got nice results regarding magnetic properties of pristine La, Nd and Dy francisites. They show strong to weak MMTs and SRTs along with nice interplay of FM and AFM interactions. The magnetic structure of BiCufr was determined from neutron diffraction. In this proposed study we want to examine magnetic structures of La, Dy, Nd francisites (LaCufr, DyCufr, NdCufr). Our aim is to find the very different magnetic structure of these proposed compounds using required magnetic structural information of BiCufr, which can solve unanswered questions arising from additional magnetic complexities due to magnetic RE incorporation at non-magnetic Bi site.