The results show that such magnets may contain local deformations in the crystal lattice of the material. These deformations are above all located at the boundary of material grains. According to the calculations of the St. Pölten University of Applied Sciences, the magnetic force of the material is weakened in these areas, avoided by optimising the material structure, which would save resources by reducing the amount of rare earths required.

With an annual production of 150,000 tonnes, rare earths are not that rare, but they are difficult to extract. In view of rapidly growing global demand, a shortage is imminent. Due to their particular chemical properties, rare earths are sought after for modern environmental technology.

High-end computer simulations, such as the computations from St. Pölten University of Applied Sciences,  whose scientists have studied the exact structure of neodymium magnets where on addition to the rare earth element neodymium, magnets comprise iron and boron, could make a major contribution to optimisation. .

CRYSTAL CRISES
Head of  Industrial Simulations study, Prof. Thomas Schrefl, noted: "Our simulations show disturbances in the neodymium magnets crystalline structure, causing the magnetising direction to change in these areas. In a so-called anisotropic magnet, like the neodymium magnet, in which all parts must have the same magnetising direction, the phenomenon weakens the magnet." 

The team´s simulations show that such disturbances in the junctions between individual material grains occur when three different grains meet In  triple junctions, and a non-magnetic enclosure is formed with the crystal lattice near the enclosure being disturbed. In the same region, a high demagnetising field weakens the magnet further.

The influence of disturbances on the magnet´s behaviour were found in multiscale simulations that take into account several different dimensions: from the atomistic to the visible range. Conventional simulations were unable to cover this range of size until now.

It was the combination of individual numerical computational methods, such as fast boundary element methods and tensor grid methods for computing the magnetic fields, which finally made it possible and was achieved by Prof. Schrefl´s team as part of the Special Research Program, Vienna Computational Materials Laboratory (ViCoM) . 

COHESION THROUGH MOVEMENT
Prof. Georg Kresse (left) from the research group Computational Materials Physics at the University of Vienna, explained the aims of the Special Research Program: "We want to describe the correlated movement of electrons more accurately. This electron correlation is mainly responsible for the cohesion of solid-state bodies and molecules. An accurate description is therefore crucial for precisely predicting the mechanical, electronic and optical properties of materials."

In a total of twelve project groups, more than 50 scientists are working on describing material properties,  of key importance to numerous technologies of tomorrow, including microelectronics, solar technology and polymer production.

The Special Research Program helps with the optimisation of magnetic and magneto-optical storage, as in high-performance permanent magnets for electric cars or wind turbines, making a substantial contribution to developing future-oriented technologies.