Magnetization, Magnetic Susceptibility and ESR in Tb3Ga5O12

We report on the measurement of the magnetic susceptibility and of ESR transitions in the garnet substance Tb${}_3$Ga${}_5$O${}_{12}$ (TGG). The results are compared with a calculation in the framework of crystal field theory for the orthorhombic surroundings of the six inequivalent Tb ions of TGG. We also present a calculation of the magnetization for the three main crystal directions.