Bismuth-substituted rare earth iron garnet single crystal film

摘要

A BIG film for a Faraday rotator is provided with a first antireflection film on the front surface and a second antireflection on the back surface. The first and second antireflection films differ in material or thickness and therefore differ in color. The difference in color makes it possible to visually distinguish the front surface from the back surface. The antireflection films of different colors may be applied to a BIG film with a square hysteresis which retains its magnetic saturation after an external magnetic field has been removed.