Switching field distribution of magnetic fine particles

In the magnetic recording media the switching field distribution (SFD) is a n important micromagnetic characteristic curve. However, in general case, m ethods of assessing SFD have not presented a reasonable relation between th e macroscopic measurements and the microscopic properties of the system. Th e degree of alignment of particles easy axis in a texture and the angular d ependence of switching field are two fundamental factors for the distributi on function. A technique for determining the switching field distribution c urve due to these factors is reported. This technique is per-formed for tex tured iron fine particles and samples of CrO2 and gamma Fe2O3 commercial ta pes. The distribution differs from a gaussian function. However, the width and the mean switching field equal to twice of the width of dM(r)/dH curve and the remanent coercivity, respectively. Furthermore, it is shown that th e width of the switching field distribution decreases with increasing the d egree of easy axis orientation. (C) 2001 Elsevier Science B.V. All rights r eserved.