Electronic Structures and Noncollinear Magnetic Properties of Structurally Disordered Fe

Abstract

The magnetic properties of amorphous Fe were investigated by examining the electronic structures of structurally disordered Fe systems generated from crystalline bcc and fcc Fe using a Monte-Carlo simulation. As a rst principles band method, the real space spin-polarized tight-binding linearized-mun-tin-orbital recursion method was used in the local spin density approximation. Compared to the crystalline system, the electronic structures of the disordered systems were characterized by a broadened band width, smoothened local density of states, and reduced local magnetic moment. The magnetic structures depend on the short range configurations. The antiferromagnetic structure is the most stable for a bcc-based disordered system, whereas the noncollinear spin spiral structure is more stable for a fcc-based system.

Finite-size effects in amorphous Fe90Zr10/Al75Zr25 multilayers

“…This reflects an increased importance of exchange frustration and random anisotropy, which are responsible for an increasingly non-collinear arrangement of the magnetic moments with decreasing temperature. 30,31,[36][37][38][39] The FC magnetization curves of the multilayer samples also show maxima or plateaus. However, these are much weaker and appear at lower temperatures as compared to the 300 Å film.…”

“…21,22 There exists a wealth of reports on the bulk properties of amorphous FeZr alloys from both experimental [23][24][25][26][27][28][29][30][31][32][33][34][35] and theoretical studies. [36][37][38] Currently there is no generally accepted view on the description of the magnetic structure at the atomic-scale, although several models have been proposed. These include the 'wandering axis' model, in which the axis of the local ferromagnetic order changes direction over short distances, 28 the freezing of the transverse components of the magnetization at low temperature, 33 the formation of antiferromagnetic spin clusters in a ferromagnetic matrix 23,26,27 and the arrangement of the moments in finite, interacting, non-collinear spin clusters 32,34 or non-collinear clusters embedded in an infinite ferromagnetic matrix.…”