Magnetic Anisotropy Induced by Magnetic and Stress Annealing in Co, Co–Ni and Co–Fe Alloys

Abstract

Optical interferometer displacement sensors are well known for their high resolution, up to 10 −7 m in a stabilized environment, over a wide measuring range which can reach several metres. Moreover, the measurements are carried out without any mechanical contact with the target object. Two optical outputs are however needed to determine the displacement sign. A glass integrated sensor with only one optical output that still measures the displacement sign is proposed here. It is derived from a Michelson interferometer but is realized by ion exchange on a glass substrate. A piezoelectric element placed over the reference arm produces a longitudinal acoustic wave that creates a small phase modulation in the reference light beam at a high frequency (1.28 MHz). A small modulation of the output signal is thus produced. The direction determination is based on the comparison between the phases of the excitation acoustic signal and of the high frequency part of the sensor's output signal after proper signal processing. A theoretical and an experimental demonstration of that principle are presented. A precision of 158 nm was obtained with simple numerical signal processing.

Transmission electron microscopy study of large field induced anisotropy (Co1−xFex)89Zr7B4 nanocomposite ribbons with dilute Fe-contents

“…However, there is also the possibility of additional microstructural mechanisms active for the FCC and HCP phase that are not active in the BCC phase. The potential sources of such microstructural mechanisms include crystallographic texture or planar defects which were suggested as possible sources of K U in previous work on bulk Co-rich Co-Ni crystalline alloys subject to field annealing in order to undergo martensitic transformations between the FCC and HCP phases [8].…”

“…Particularly relevant to the alloys under investigation here, stacking faults have been proposed as the source of magnetic anisotropy observed after plastic deformation of FCC-based dilute Fe-containing bulk Co-Fe alloys [9]. In the interest of brevity, the reader is referred to previous works for a discussion of stacking faults as a potential source of field induced anisotropy [8,9].…”

“…Because planar defects such as stacking faults have also been proposed as a possible source of induced anisotropy in previously studied Co-rich alloys [8,9], high-resolution transmission electron microscopy (HRTEM) was performed on selected field crystallized samples (T Anneal = 540 1C) to more carefully probe the microstructure of these multi-phase nanocomposites.…”