Magnetic spins that ‘freeze’ when heated: Nature in the wrong direction

Nanowerk  July 4, 2022 An international team of researchers (the Netherlands, Sweden) observed an unusual magnetic transition in elemental neodymium where, with increasing temperature, long-range multiply periodic ‘multi-Q’ magnetic order emerged from a self-induced spin glass. They characterized the local order of a previously reported spin glass phase and quantified the emergence of long-range multi-Q order with increasing temperature. Using the analysis tools they developed, they determined the glass transition temperature from measurements of the spatially dependent magnetization. They compared these observations with atomistic spin dynamics simulations to reproduce the qualitative observation of a phase transition from a low-temperature spin […]

Printing circuits on rare nanomagnets puts a new spin on computing

Phys.org  March 28, 2022 An international team of researchers (USA – Argonne National Laboratory, Lawrence Livermore National Laboratory, Switzerland, the Netherlands, Finland) combined theoretical and experimental work to fabricate and observe the artificial spin glass as a proof-of-principle. Hopfield neural network mathematically models associative memory to guide the disorder of the artificial spin systems. They performed temperature-dependent imaging of thermally driven moment fluctuations within these networks and observed characteristic features of a two-dimensional Ising spin glass. They observed clear signatures of the hard-to-observe rugged spin glass free energy in the form of sub-aging, out-of-equilibrium autocorrelations and a transition from stable […]