EXTENSIONS OF THE GEOMETRIC SOLUTION OF THE 2-DIMENSIONAL COHERENT MAGNETIZATION ROTATION MODEL

The problem of the determination of the orientation of a (classical) m agnetic moment submitted to an applied field in the presence of an arb itrary anisotropy energy function is investigated theoretically, in tw o dimensions. The framework is the geometrical method introduced by Sl onczewski. After rederiving Slonczewski's results in general terms (i. e. not only in the uniaxial case), extensions and additional propertie s of the geometric solution are described. An orientation of the criti cal curve is proposed, a geometrical evaluation of the energy demonstr ated, the determination of the anisotropy function by means of switchi ng field angular measurements is discussed and finally, the critical c urves are completely characterized. This geometrical solution has seve ral applications. First, it visualizes directly the dependence of the particle switching field on field orientation. Second, it gives simple analytical formulae for the energy barrier close to switching. This q uantity is relevant in the study of the reversal of single-domain part icles. (C) 1998 Elsevier Science B.V. All rights reserved.