Sharif Digital Repository

In a magnetic recording media, anisotropic particles are placed with different directions in the head field. The switching field, Hs of a particle at a certain direction is defined as the minimum field, which reverses its easy axis magnetization. To determine the position of magnetization transition in recording media, one needs the angular dependence of the switching field. To find this for a texture of anisotropic single domain particles, the acicular iron particles with 0.3 μm length have been grown in a magnetic field. Then, the textures of the particles have been oriented by another magnetic field. We have measured the remanent magnetization of samples mr(θ) and mr(H), respectively, as... 

The unsymmetrical tetradentate Schiff base H2L was prepared by the reaction of salicylaldehyde with the mono Schiff base derived from o-phenylenediamine and o-hydroxyacetophenone (HL1). NiL and CuL complexes were prepared and characterized by 1H NMR, IR and single crystal X-ray structure determination. Crystal data for NiL: triclinic space group P-1, a = 7.190 (2) Å, b = 13.059 (4) Å, c = 17.867 (10) Å, α = 74.888 (10)°, β = 84.206 (10)°, γ = 86.542 (2)° and z = 4. Crystal data for CuL: monoclinic space group P2I/n, a = 12.8209 (6) Å, b = 6.988 (3) Å, c = 18.601 (9) Å, β = 105.15° and z = 4. The Ni and Cu atoms have a slightly distorted square-planar coordination geometry  

In the magnetic recording media the switching field distribution (SFD) is an important micromagnetic characteristic curve. However, in general case, methods of assessing SFD have not presented a reasonable relation between the macroscopic measurements and the microscopic properties of the system. The degree of alignment of particles easy axis in a texture and the angular dependence of switching field are two fundamental factors for the distribution function. A technique for determining the switching field distribution curve due to these factors is reported. This technique is performed for textured iron fine particles and samples of CrO2 and γFe2O3 commercial tapes. The distribution differs...