Modeling of a Micromagnetic Imprinting Process

Abstract

In this article, we present the magnetic modeling of a batchfabrication process to imprint microscale pole patterns in hardmagnetic thick films. The imprinting process enables the creation of complex magnetic field patterns from permanent magnetic layers. The selective magnetic imprinting and the resultant stray fields are modeled in a two-step process using COMSOL Multiphysics in conjunction with measured magnetic hysteresis behavior. The models are used to evaluate the process design space and to predict the resulting stray magnetic field distribution in a patterned, 10-µm-thick Co-Pt magnetic film.

Magnetic Assembly and Cross-Linking of Nanoparticles for Releasable Magnetic Microstructures

“…A magnetic reversal field of ∼200 mT was used to generate the magnetization pattern in the magnetic tape substrate. Because experimental measurement of the resultant microscale magnetic field gradients is quite difficult, simulations 44 were used to estimate orders of magnitude of the magnetic field and magnetic field gradient in a typical boundary between two opposing magnetic poles (refer to measured magnetic properties of the tape in Figure S3 and simulation result in Figure S4). The kinetics of the assembly process and the resultant microstructural features were studied for three process variables: (1) assembly time, (2) volume fraction of the particles in suspension, and (3) iron oxide vs cobalt ferrite nanoparticles.…”

Brownian Dynamics Simulations of Magnetic Nanoparticles Captured in Strong Magnetic Field Gradients

“…Such a situation is found, for example, in perpendicular recording media, where specific areas of a thin magnetic layer (e.g., films, substrates, tapes, hard drives) are magnetized out of plane, in opposite directions of the original magnetization of the layer. To understand this behavior, a twodimensional (2D) magneto-static finite-element simulation 26 was used to estimate the magnetic field at a magnetic pole boundary in a magnetic substrate (Hi8MP video cassette tape). 9 This simulation was carried out using the ac/dc module in the COMSOL Multiphysics software (version 5.1), using "magnetic fields, no current" (mfnc) as the physics.…”