1/24/2024 0 Comments A.t.o.m. 227![]() Petersburg (Russia), and Sendai (Japan) have now revealed the elementary steps of this process. In the framework of the CRC/TRR 227 at the Freie Universität Berlin, a team of scientists from Berlin, Dresden (Germany), Uppsala (Sweden), St. Previous estimates of this time scale differ from each other by a factor of up to one million. Even for the ferrimagnet yttrium iron garnet (YIG), one of the most intensely researched ferrimagnets, it is unknown how long it takes until the heated atomic lattice and the cold magnetic spins reach equilibrium with each other. ![]() Although this process is of fundamental importance, its dynamics are not well understood. Thus, magnetic order gets lost the total magnetization (M 1-M 2) decreases and eventually vanishes if the temperature of the ferrimagnet exceeds a critical temperature, the so-called Curie temperature. Finally, part of the heat also causes random rotation (precession) of the spins around their cold direction. When an insulating ferrimagnet is heated, the heat is first deposited in the atomic lattice which causes the atoms to move randomly around their cold positions. Due to the opposite direction, the magnitude of the total magnetization is M 1-M 2. ![]() Thus, the total magnetization is the sum of all magnetic moments of type 1 (M 1, blue arrows) and type 2 (M 2, green arrows). In a ferrimagnet, the magnetic moments point in opposite directions for the two types of atoms (see panel A). Similar to a compass needle, each atom exhibits a little magnetic moment, also called spin, which arises from the rotation of the atom’s electrons about their own axes. Ferrimagnets form the largest class of magnets and consist of two types of atoms. Magnets have fascinated humans for several thousand years and enabled the age of digital data storage. What happens when we heat the atomic lattice of a magnet all of a sudden
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