The defining length scales of mesomagnetism: a review

Abstract

This review is intended as an introduction to mesomagnetism, with an emphasis on what the defining length scales and their origins are. It includes a brief introduction to the mathematics of domains and domain walls before examining the domain patterns and their stability in 1D and 2D confined magnetic structures. This is followed by an investigation of the effects of size and temperature on confined magnetic structures. Then, the relationship between mesomagnetism and the developing field of spin electronics is discussed. In particular, the various types of magnetoresistance, with an emphasis on the theory and applications of giant magnetoresistance and tunnelling magnetoresistance, are studied. Single electronics are briefly examined before concluding with an outlook on future developments in mesomagnetism.

Superferromagnetism in chain-like Fe@SiO2 nanoparticle ensembles

“…[1][2][3][4] In particular, metal nanoparticles have attracted the attention of the scientific community because of their applications in information storage technologies or in biomedicine as contrast agents for magnetic resonance imaging, carriers in drug or gene delivery systems, or materials for hyperthermal treatment of tumors. [5][6][7] However, the above mentioned physical properties can be significantly affected by competing interactions between nanoparticles.…”

Bit Storage by 360$^{\circ}$ Domain Walls in Ferromagnetic Nanorings

“…Magnetoresistive Random Access Memory (MRAM) has long been considered as one of the main contenders to replace the current semiconductor-based devices as a universal, non-volatile computer memory 1,2,3,4 . Nevertheless, despite recent developments of commercially available products 1 , MRAM technology is yet to deliver a device that would truly compete with the existing semiconductor technologies.…”

“…• walls are accessible by smooth in-plane rotation of the magnetization vector from the "onion" state 2,6,8,15 , the native magnetization state in the ring following saturation by an in-plane field. Switching between these states is achieved by passing a current of variable polarity through a wire running perpendicularly to the ring plane through its center, generating a circular magnetic field in the ring, and readout can be performed, as in previous designs, by arranging the ferromagnetic nanoring to be part of a magnetic tunnel junction sandwich, with fixed ferromagnetic ring layer in a vortex state.…”

Order and Frustration in Artificial Magnetic Patterns

“…Modern lithographic techniques enable the fabrication of lateral magnetic patterns of various sizes, shapes, and periodicities on a nanometer to micrometer scale [1,2]. Of particular interest are artificial magnetic dipoles, which can be arranged on lattices with a variety of symmetries [3,4].…”