Magnetoreactance Studies in Rare Earth-Doped Ni Ferrite

Structural, electrical, and magnetoreactance (mr) characteristics of rare earth-doped Ni ferrite (NiO.Fe
_2-x
R
_x
O
₃

(x = 0, 0.075, R = Dy, Gd)
, and NiO.Fe
_1.95
R
_0.05
O
₃

(R = Gd, Nd)
) were investigated. All the materials formed in the cubic inverse spinel phase with small amounts of RFeO
₃
as the additional phase. mr was measured in both longitudinal and transverse configuration. A mr of
-1477%
was observed for pure nickel ferrite at 10 kHz while it is smaller for the rare earth-doped compounds. With increasing frequency maximum mr value is found to decrease. The resistivity was found to decrease with increasing frequency for all the compounds and dispersion of relaxation times was observed.