New features in rare earth based zero magnetization spin ferromagnets

Abstract

A ferromagnetic rare earth (RE) intermatallic can be made to imbible zero magnetization characteristic and display magnetic reorientation phenomenon by letting a RE site be occupied at random by two RE atoms belonging to different halves of 4f series (Gd to be counted alongwith second half) and choosing their fractional compositions appropriately. In recent times, H. Adachi and co-workers drew specific attention to ferromagnetic Sm based systems, where the net moment can be either ‘orbital surplus’, or ‘spin surplus’ (due to admixture effects) and the zero magnetization state can be obtained by substitution of Sm by the Gd or Nd. We present here a status report of our investigations and describe newer features related to magentic compensation phenomenon in a wide variety of RE system. In particular, our studies reveal that (i) the notion of spin flip transition across the temperature region of magnetic compensation is a generic behavior, (ii) it can happen in a re-entrant manner in specific circumstances, (iii) it survives strong hybridization effects that can happen for Ce³⁺ ions, e.g., in CeRh₃B₂, and compromise ferromagnetic exchange interaction between diddimilar RE spins, etc.