Low-damping sub-10-nm thin films of lutetium iron garnet grown by   molecular-beam epitaxy
  We analyze the structural and magnetic characteristics of (111)-oriented lutetium iron garnet (Lu$_3$Fe$_5$O$_{12}$) films grown by molecular-beam epitaxy, for films as thin as 2.8 nm. Thickness-dependent measurements of the in- and out-of-plane ferromagnetic resonance allow us to quantify the effects of two-magnon scattering, along with the surface anisotropy and the saturation magnetization. We achieve effective damping coefficients of $11.1(9) \times 10^{-4}$ for 5.3 nm films and $32(3) \times 10^{-4}$ for 2.8 nm films, among the lowest values reported to date for any insulating ferrimagnetic sample of comparable thickness. 
C. L. Jermain, H. Paik, S. V. Aradhya, R. A. Buhrman, D. G. Schlom,   and D. C. Ralph
cond-mat.mes-hall cond-mat.mtrl-sci