NdFe(B) thin films are deposited onto glass substrates by means of a tungsten crucible. The as‐deposited films are studied by the Lorentz microscopy method in order to observe the different magnetic domains. STEM analysis (EELS method) permits us to obtain the characteristic absorption edges of Fe and Nd (but not of boron). The crystallization behavior, inside the electron microscope, by means of the electron beam, allows us to observe the formation of the &agr;‐Fe,A‐Nd2O3, and NdFeO3phases. The different stages of appearances of these structures are discussed.