Magnetic Moments of Some Mixed Rare Earth Iron Garnets

The maximum amount of substitution of La, Pr and Nd and the saturation magnetization of La, Pr, Nd, Sm and Eu substitutions in the iron garnets of Lu, Yb, Tm and Er was measured. It was found that in a formula R 3- x M x Fe 5 O 12 where R=Lu, Yb, Tm and M=La, Pr or Nd the maximum value of x which can be substituted in the garnets was x =0.50 for La, x =1.50 for Pr ( x =1.35 for Pr in Er.I.G.) and x =1.85 for Nd ( x =2.00 for Nd in Lu.I.G.). The sign of the magnetic moment of the mixed rare earth ions relative to the net iron magnetization was determined. It was found that Pr 3+ or Nd 3+ are parallel whereas Eu 3+ , Er 3+ , Tm 3+ and Yb 3+ antiparallel to the net iron magnetization. For Sm 3+ a small magnetic moment is guessed and discussed.