Unconventional spin textures in magnetically frustrated topologies
Frustration is a general concept in physics and can be found in many condensed matter systems. Frustration arises when all pairwise interactions can not be satisfied simultaneously, for example due to the system geometry. In some cases, frustration effects lead to an extensively degenerate ground state, i.e a low-temperature manifold built with a infinite number of configurations with identical energy. Frustrated systems may then have a finite entropy, even at zero temperature.
Progress in fabrication and characterization techniques allowed researchers to produce, artificially, two-dimensional frustrated arrays of nanostructures and to investigate their collective magnetic behavior. These studies have stimulated new research activities motivated by the quest for exotic magnetic phases in condensed matter physics, bringing together the communities of magnetic frustration, statistical physics, and nanomagnetism.
In different contributions, we showed experimentally (magnetic imaging techniques) and theoretically (mainly Monte Carlo simulations), that simple magnetic topologies can lead to unconventional spin textures. For example, kagome arrays of ferromagnetic nano-islands with ferromagnetic nearest neighbor interactions do not show magnetic order. Instead, these systems are characterized by spin textures with intriguing properties, such as chirality, coexistence of magnetic order and disorder, and charge crystallization. However, in kagome arrays of ferromagnetic nano-disks with antiferromagnetic interactions between neighboring elements (see Figure), the system is also characterized by an unusual magnetic phase, but with a still unknown spin texture.
In physics as in chemistry, it is generally accepted that matter orders, like in a crystalline solid, when cooled at sufficiently low temperature. There also exist systems that remain disordered in the manner of a gas or a liquid, even at the lowest temperatures accessible experimentally. What... > suite
Frustration is a general concept in physics and can be found in many condensed matter systems. Frustration arises when all pairwise interactions can not be satisfied at once, for example due to the system geometry. In some cases, frustration effects lead to an extensively degenerate ground state, i.e a low temperature manifold built with a large number of configurations with identical energy. Pauling’s description of the low-temperature proton disorder in water ice was perhaps the first example of frustration in condensed matter physics, and remains its paradigm. [...]