Ev. Tartakovskaya et al., Self-consistent theory and simulation of quasiuniform states in thin rectangular magnetic nanoparticles, J APPL PHYS, 89(12), 2001, pp. 8348-8350
A self-consistent theory of the ground-state nonuniform magnetization distr
ibution in small magnetic nanoelements is proposed, valid for thicknesses m
uch less than the exchange length, and with natural fulfillment of boundary
conditions allowing application to a variety of element shapes. The theory
is applied to rectangular 2p(1)l x 2p(2)l x 2l permalloy elements. In cont
rast to that of square elements, there exists a range of particle sizes hav
ing an "intermediate" ground state (mixed flower and leaf symmetries) with
average magnetization inclined at phi to the longer edge. With increasing p
(1)/p(2) (p(2) fixed), phi gradually decreases to zero (flower state). This
intermediate-->flower transition is of the second type, unlike the leaf-->
flower transition (first type) observed in square elements with reduction i
n p(1)(=p(2)). Simulation results support the analytic theory. (C) 2001 Ame
rican Institute of Physics.