Characterization of paramagnetic materials by low-temperature magnetization

A new method of analysis of low-temperature magnetization is presented for materials containing small amounts of randomly distributed magnetic ions. It is shown that, in the case of noninteracting ions, the magnetic field H-eq, corresponding to the intercept of extrapolated linear parts of low- and high-field magnetization, does not depend on the magnetic entities concentration x and provides basic information on their magnetic moment, allowing, in turn, for a precise determination of x. It is also shown that, when the magnetic ions start to interact between themselves, H-eq shifts towards higher fields and is closely related to the parameter T-0 entering into the modified Brillouin function. The usefulness of the presented method is illustrated by the analysis of results obtained for a number of dilute magnetic semiconductors containing small amounts of transition metal ions. (C) 1999 Elsevier Science B.V. All rights reserved.