Domain structure of CoNi microparticles under mechanical stress

Abstract

In this work, the results of the study of the domain structure of planar CoNi microparticles are presented. The microparticles represented squares with a side of 7 μm and height of 0.03 μm. It was shown that in the non-stressed state the particles had the regular four-domain state. The mechanical stress (compression) of the particles led to a change in domain size, which depended on the degree of compression, the angle between the direction of magnetization, and the side of the mechanical stress. Under the mechanical stress, the change in the coercive force and the residual magnetization of the particles was observed.

Thermally Induced Magnetoelastic Effect in Planar CoNi Microparticles on Lithium Niobate

“…Its saturation magnetostriction constant [ 23 ] ( λ s ) is −25 × 10 −6 and the thermal expansion coefficient [ 24 ] is . The deposition by electron beam evaporation through a metal mesh with square holes tightly pressed to the substrate surface was performed in ultrahigh vacuum [ 15,17 ] at two temperatures: 300 and 400 K.…”

“…Figure 2c shows a scheme of the possible arrangement of domains in such microparticle calculated in Object Oriented MicroMagnetic Framework (OOMMF). According to MOKE, [ 17 ] in the absence of perturbations the microparticles of this shape and compound usually have two hard axis along sides of the square and two easy axis (EA) directed along diagonals.…”

“…This is in good agreement with the results of inducing mechanical stresses in microparticles by bending the glass substrate. [ 17 ]…”

“…The magnetic force microscopy (MFM), [ 1,15–17 ] magneto‐optical Kerr effect (MOKE), [ 1,6,7,15 ] ferromagnetic resonance (FMR), [ 1,11,12,18 ] magnetorefractive effect, [ 19 ] and photoemission electron microscopy (PEEM) [ 20,21 ] can be used for studying the magnetoelastic effect. In our previous works, the transformation of domain structure in permalloy and CoNi microparticles under mechanical stress induced by substrate bending was studied.…”