مرکز منطقه ای اطلاع رساني علوم و فناوري - Thermal expansion of lattice parameters of some rare earth gallium garnets and magnetic bubble domain materials

Abstract :

The rare earth gallium garnets Dy3Ga5O12, Gd3Ga5O12, Sm3Ga5O12, and Nd3Ga5O12used as substrate materials and the magnetic film materials EuEr2GaxFe5-xO12( $0 \\leq x \\leq 5$ ) and EuxEr3-xGa0.7Fe4.3O12( $0 \\leq x \\leq 3$ ) have been prepared and their lattice parameters measured between room temperature and 1200°C. In the series R3Ga5O12, the room temperature lattice constant decreases linearly in the order Nd>Sm>Gd>Dy. The curve $\\Delta a/a_{0}$ (a0= lattice constant at 25°C, $\\Delta a$ = lattice constant - a0versus $T$ shows a very slight concavity over the whole temperature interval with higher values of $\\Delta a/a_{0}$ in the same order as the room temperature lattice constants. The lattice constants follow Vegard\´s law with the substitution of europium for erbium in the series EuxEr3-xGa0.7Fe4.3O12and decrease with decreasing europium content. The curves of $\\Delta a/a_{0}$ have the same shape as the rare earth gallium garnets, but with higher values of $\\Delta a/a_{0}$ in the opposite order to the room temperature lattice constants. Substitution of gallium for iron in the series EuEr2GaxFe5-xO12caused positive deviation from Vegard\´s law and a decrease in the room temperature lattice constants. The values of $\\Delta a/a_{0}$ increase with increasing iron content. The implications of these observations on the properties of magnetic films for bubble domain applications are discussed.