Influence of Nuclear Tracks on the Magnetic Properties of a(Gd,Bi)3(Fe,Ga)5O12Garnet Film

The temperature dependence of the saturation magnetization of an epitaxial ${\mathrm{Gd}}_{2.3}$ ${\mathrm{Bi}}_{0.7}$-${\mathrm{Fe}}_{4.5}$ ${\mathrm{Ga}}_{0.5}$ ${\mathrm{O}}_{12}$ garnet film irradiated with 180-MeV Xe ions of different doses has been investigated experimentally and analyzed theoretically in terms of molecular-field theory. The magnetic ordering inside the nuclear tracks turns out to be destroyed as a result of the large degree of disorder. The effective nuclear track diameter is estimated to be 15 nm. The molecular-field coefficients deduced from the magnetization curves depend on dose.