Bitter colloid observations of magnetic structures in perpendicular magnetic recording media

Abstract

In this study the Bitter colloid method has been used for domain structure observation in high coercivity Co-Cr and for observations of magnetization state of single alumite needles. Furthermore the results of bit writing experiments in Co-Cr have been observed by this method, which allows to compare samples, prepared with different parameters.

Magnetic force microscopy of thin film media for high density magnetic recording

“…The first method, however, offers a higher lateral resolution than the second. It also allows a Bitter pattern observation by scanning electron microscopy (SEM) [3] which further increases the lateral resolution of the technique to about 100 nm [4].…”

Pattern transfer nanomanufacturing using magnetic recording for programmed nanoparticle assembly

“…Magnetic gradient force directed assembly was originally employed by Bitter to visualize domains and surface features in magnetic materials [3]. This 'Bitter technique' has been applied for imaging the patterns created by magnetic recording on disk drive media [4], and for separating weakly magnetic and nonmagnetic particles through high-gradient magnetic separation (HGMS) [5]. More recently, lithographed arrays of magnetic materials biased with external magnetic fields have been used to assemble magnetic particles in a fluidic environment [6][7][8][9][10][11][12][13][14], yielding techniques for particle transport for drug delivery [15,16], masking for lithography [17], and stitched membrane assembly [18].…”

Ferromagnetic Shape Memory Heusler Materials: Synthesis, Microstructure Characterization and Magnetostructural Properties

“…The particles in the ferrofluid interact by magnetic forces and by electrostatic and van der Waals forces. The liquid is usually dried up or rinsed, leaving the colloid particles to form Bitter patterns, after F. Bitter) [60] yielded a critical boundary between the ferromagnetic and paramagnetic phases spread over a wide composition range from the Ni-rich region to the Mn-rich region.…”