For the study of the relationship between the domain wall motion (DWM) and the coercivity in the samples of Dy-free Nd-Fe-B sintered magnets, the DC susceptibility (χDC) in the initial magnetization from the thermally demagnetized state and the DWM in the partially demagnetized state after the full magnetization in 5T-pulse field were measured. In the high coercivity (μ0Hc) samples of μ0Hc=1.35...

Adviser: Shireen Adenwalla The interaction between ferromagnetic and ferroelectric films, the magnetoelectric effect, is a fascinating fundamental research area as well as having potential applications in magnetic data storage devices. We have investigated magnetoelectric coupling effects in thin film heterostructures, consists of metallic ferromagnet, cobalt, and the polymer ferroelectric [P(V...

In magnetic random access memory (MRAM), power consumption depends on the coercivity of the magnetic elements in the memory cells. In this paper a new method is described that uses a “domain wall trap” element shape to reduce both the coercivity and the dependence of coercivity on element size in submicron magnetic elements. Micromagnetic simulations of a shaped Permalloy element show coercivit...

We report experimental evidence that submicron-scale local coercivity variation determines magnetization reversal dynamics in ferromagnetic thin films. Local coercivity distribution is generated from a twodimensional array of hysteresis loops each of 0.3230.32 mm spots simultaneously measured using a magneto-optical microscope magnetometer. We directly demonstrate that domain reversal pattern i...

A reduction process of the substituted Ba-ferrite has been found to be devided into three steps. At the first and second steps, the magneto-plumbite structure maintains and the coercivity increases. When the reduced-substituted Ba-ferrite particles are reoxidized, the coercivity is reversible in the first step but irreversible in the second step. During the third step, the magneto-plumbite stru...

Single-crystal thin films of the antiferromagnet FeF2 have been used to exchange bias overlayers of Fe. An unexpected coercivity enhancement is observed at temperatures above the Néel temperature of the FeF2. This coercivity reaches a peak value of over 600 Oe close to the Néel temperature and persists to above 300 K. The coercivity is correlated with the growth of an anisotropy in the ferromag...

A magnetic field is successfully utilized to induce the fabrication of size controllable one-dimensional (1-D) supercrystals which are composed of a highly crystalline assembly of fcc-packed cobalt nanoparticles; the anisotropy associated supercrystal magnetism is enhanced with four times higher coercivity than that of randomly aggregated nanoparticles.