TEMPERATURE-DEPENDENT MAGNETIC-PROPERTIES OF (Y,SM,LU,TM,CA)3(FE,GE)5O12 EPITAXIAL GARNET-FILMS

Thulium has been substituted for yttrium in melts for the growth of (Y,Sm,Lu,Ca)3(Fe,Ge)5O12 epitaxial garnet films for the purpose of reducing the magnitude of the temperature coefficient αbc of the bubble collapse field. As an extension of previous substitutions [J. E. Davies, G. Galli, and J. C. Suits, J. Appl. Phys. 49, 1859 (1978)] of Tm for Lu to smaller bubble diameters, growth conditions were adjusted to produce films of nearly identical thickness (1.40 μm) and characteristic length (0.222 μm at 25°C) for Tm substitutions up to 0.25 atoms in the formula unit. This substitution was found to decrease the magnitude of αbc as measured at 50°C by approximately 0.04%/°C·Tm atom. Anisotropy remains nearly constant with Tm substitution.