Effective Anisotropy in Polycrystalline Materials. Separation of Components

Abstract

A method is proposed to determine the over-all anisotropy K in ferrimagnetic materials from initial susceptibility of single-domain grain samples. Indications on technology of single-domain grain samples are given. The Ni1−xZnxFe2O4 system is studied in detail. The upper limit of the contribution from dipolar energy has been determined by studying Mn0.5Zn0.5Fe2O4 and is found to be negligible. The study of magnetoelastic anisotropy has been carried out on compositions of known K1. This anisotropy (expressed as λsσ) varies very little at low temperatures depending on Zn content, and for a given composition it varies as λs. Thus, σ is temperature independent. σ is shown to be an intrinsic property for a composition and it increases with Zn content. Our investigations show that realization of single-domain grain samples enables us to obtain σ and K1 from measurements of (μ − 1)c, Ms, and λs, which are easily accessible from polycrystalline samples.

Pressure Dependence of the Frequency Permeability Spectra of Soft Ferrite Composite Materials: A Method of Measuring the Natural Ferromagnetic Resonance Frequency

“…They are in agreement with published data [7]. The obtained values for are also consistent with published data on the magnetocrystalline anisotropy constant K [11].…”

Effect of sintering temperature on structural and magnetic properties of NiCuZn and MgCuZn ferrites

“…Saturation magnetization (M s ) and initial permeability (m i ) show similar trend with increase in sintering temperature. This indicates that the initial permeability is directly proportional to the saturation magnetization obeying m i pM 2 s [25]. NiCuZn ferrite samples have higher saturation magnetization than those of MgCuZn ferrite samples.…”

Influence of zinc substitution on magnetic and electrical properties of MgCuZn ferrite nanocrystalline powders prepared by sol–gel, auto-combustion method

“…8 ration magnetization were highest at the substitution x = 0.63 (see Table 1). The initial permeability shows that the dependence of i with zinc content (x) follows the trend of saturation magnetization obeying i ␣ M 2 s [14]. The increase in permeability and magnetization may be primarily originated from the substitution of nonmagnetic Zn 2+ for Mg 2+ ions in to the magnetic ferrite lattice.…”