Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Some magnetic properties of simple‐cubic disordered ferromagnets with fluctuating exchange integral are investigated with the use of the 1‐st, 2‐nd, and 3‐rd Matsudaira approximations. The results of various approximations are similar only for small fluctuations. For large fluctuations significant differences appear. This indicates that for a proper description of disordered material besides the simple decoupling of correlation functions, also another commonly used approximations should be significantly improved.</jats:p>