Control of the growth-induced magnetic anisotropy in ferrimagnetic garnet films grown by liquid-phase epitaxy

Abstract

The influence of melt composition and growth temperature T g on the growth-induced magnetic anisotropy constant K g u in Bi substituted LPE ferrimagnetic garnet films has been investigated. In films grown from Bi 2O 3 based and from PbO B 2 O 3 based melts the value of K g u increased upon decreasing T g, associated with an increasing incorporation of B1. However, at given Bi content the films grown from Bi 2O 3 based fluxes generally exhibited smaller values of K g u than those from PbO B 2 O 3 based melts. The addition of small amounts of Ca 2+ to the Bi 2O 3 based melts resulted in (Y,Bi)-garnet films changing from n- to p-type electrical conductivity at a minimum value of K g u. Additions of Si 4+ to a PbO B 2 O 3 based melt reduced the uniaxial magnetic anisotropy of La-YIG-Ga films accompanied by a change from p- to n-type conductivity. Similarly, (Gd,Bi)-garnet films from PbO B 2 O 3 based melts changed from n- to p-type conductivity upon decreasing T g where K g u changes sign from negative to positive. From the temperature dependence of the electrical conductivity the electron and hole concentrations in some of these films were estimated suggesting that the sign change of K g u in the investigated (Gd,Bi)-garnet films and the minimum of K g u in the investigated (Y,Bi)-garnet films and (La,Y)-garnet films occur at donor-acceptor compensation. This experimental evidence led us to conclude that the growth induced magnetic anisotropy may be correlated with the presence of donor and acceptor centers in the garnet structure.