Paper “Micromagnetics of shape anisotropy based permanent magnets” accepted for Journal of Magnetism and Magnetic Materials (JMMM)
Our new paper titled “Micromagnetics of shape anisotropy based permanent magnets” has been accepted for publication in Journal of Magnetism and Magnetic Materials (JMMM).
Visualizations of the computed magnetization data during reversal of soft prolate spheroids for aspect ratios (a) 1.95 and (b) 15.6, showing the different reversal modes.
Permanent magnets are important components in electrical generators and motors, among other technologies, and they are critical to the operation of wind turbines and electric/hybrid cars. Currently, all high-performance permanent magnets contain expensive rare earth elements such as Nd and Dy. We want to design new magnets that are cheaper and create less environmental damage through mining. One way to do this is with new magnets that are nanostructured to take advantage of shape effects.
In the paper we use micromagnetics simulations to assess the limits of shape contributions to the reversal stability of soft and semi-hard elongated magnetic particles.
We show that in materials with moderate uniaxial magnetocrystalline anisotropy the addition of shape anisotropy can double the coercive field.
In soft magnetic cylinders nucleation of a reversed domain starts at the corners at the end and smoothing the edges can improve the coercive field by about 10 %.
In further simulations we compacted soft magnetic cylinders into a bulk-like arrangement, where misalignment and magnetostatic interactions cause a spread in the switching field. We also show that magnetostatic interactions reduce the coercive field in compacted rod arrangements by up to 20 %.