Structural, Magnetic Properties and Mssbauer Analysis of R2Fe17-xTMx (R: Dy, Er & Gd, TM: Nb & Cr) Compounds.

Binary rare-earth (R)-iron intermetallic compounds with Th2Ni17 and Th2Zn17 structure have been extensively studied for their potential application as permanent magnets. The main drawbacks of these materials are low Curie temperature (Tc) and magnetic anisotropies. In the present study, substitution of Fe atom by Nb or Cr atom shows enhancement in the magnetic properties of R2Fe17 compounds.On the first part of thesis, it presents effects of substituting iron atoms in R2Fe17 (R: Dy & Er) with bigger non-magnetic Nb atoms and smaller magnetic Cr atoms with changes in the structural and magnetic properties of the R2Fe17-xNb(orCr)x (0 ≤ x ≤ 1.5 for Nb and 0 ≤ x ≤ 3.0 for Cr) compounds. The maximum Tc was observed at x = 1. Other part of the thesis, ball milling on Er2Fe16Nb1, Dy2Fe16Nb1 and Gd2Fe16Nb1 compounds shows enhancement in the magnetic properties and Tc due to exchange spring behavior