Magnetic and transport properties of HfFe6Ge6-type REMn6X6-xX '(x) solid solutions (RE = rare earth; X = Ge, Sn; X = Ga, In)

An overview of current research in the field of REMn6X6-xX'(x) solid solutions (RE = rare earth metals; X = Ge, Sn; X' = Ga, In) with the HfFe6Ge6-type structure is presented. The substitution results in a tuning of Mn-Mn interlayer interactions and a continuous transition from antiferromagnetism to ferromagnetism with increasing value of x. The effect of thermal and hydrostatic pressure on the magnetic ordering has been studied. The compounds display giant magnetoresistance (MR) and anisotropic transport properties in relation with the magnetic ordering, consistent with expectations from preliminary electronic structure calculations. The study of those compounds containing paramagnetic rare earths allows a better understanding of the magnetocrystalline anisotropy, which is dominated by the fourth-order crystal-field parameter