Observation of domain wall pinning in Dy/sub 0.73/Tb/sub 0.27/Fe/sub 2-x/Ni/sub x/ and Ho/sub 0.85/Tb/sub 0.15/Fe/sub 2-y/Ni/sub y/ systems

Magnetization studies were carried out on the cubic Laves phase Dy/sub 0.73/Tb/sub 0.27/Fe/sub 2-x/Ni/sub x/ and Ho/sub 0.85/Tb/sub 0.15/Fe/sub 2-y/Ni/sub y/ [x=y=0, 0.5, 1.0, 1.5 and 2.0] systems at 4.2 K. These studies indicate that the magnetization process is influenced by the domain wall pinning. The value of the propagation field observed increases with Ni concentration in both the systems up to x=y=1.5 and falls to a small value for x=y=2.0. The pinning effect is more pronounced in the case of Dy/sub 0.73/Tb/sub 0.27/Fe/sub 2-x/Ni/sub x/ when compared with Ho/sub 0.85/Tb/sub 0.15/Fe/sub 2-y/Ni/sub y/ because of the larger K/sub 1/ value for Dy/sub 0.73/Tb/sub 0.27/Fe/sub 2/ compared to Ho/sub 0.85/Tb/sub 0.15/Fe/sub 2/.