Magnetic skyrmions are well-suited for encoding information because they are nano-sized, topologically stable, and only require ultra-low critical current densities jc to depin from the underlying atomic lattice. Above jc, skyrmions exhibit well-controlled motion, making them prime candidates for race-track memories. In thin films thermally-activated creep motion of isolated skyrmions was observed below jc as predicted by theory.
Using Uniaxial Stress to Probe the Relationship between Competing Superconducting States in a Cuprate with Spin-stripe Order
We report muon spin rotation and magnetic susceptibility experiments on in-plane stress effects on the static spin-stripe order and superconductivity in the cuprate system La2−xBaxCuO4 with x = 0.115. An extremely low uniaxial stress of ∼0.1 GPa induces a substantial decrease in the magnetic volume fraction and a dramatic rise in the onset of 3D superconductivity, from ∼10 to 32 K.
Here we investigate antiferromagnetic Eu5In2Sb6, a nonsymmorphic Zintl phase. Our electrical transport data show that Eu5In2Sb6 is remarkably insulating and exhibits an exceptionally large negative magnetoresistance, which is consistent with the presence of magnetic polarons. From ab initio calculations, the paramagnetic state of Eu5In2Sb6 is a topologically nontrivial semimetal within the generalized gradient approximation (GGA), whereas an insulating state with trivial topological indices is obtained using a modified Becke−Johnson potential.
Z3-vestigial nematic order due to superconducting fluctuations in the doped topological insulators NbxBi2Se3 and CuxBi2Se3
A state of matter with a multi-component order parameter can give rise to vestigial order. In the vestigial phase, the primary order is only partially melted, leaving a remaining symmetry breaking behind, an effect driven by strong classical or quantum fluctuations. Vestigial states due to primary spin and charge-density-wave order have been discussed in iron-based and cuprate materials. Here we present the observation of a partially melted superconductivity in which pairing fluctuations condense at a separate phase transition and form a nematic state with broken Z3, i.e., three-state Potts-model symmetry.
Quantum materials that feature magnetic long-range order often reveal complex phase diagrams when localized electrons become mobile. In many materials magnetism is rapidly suppressed as electronic charges dissolve into the conduction band. In materials where magnetism persists, it is unclear how the magnetic properties are affected.
Visualization and quantification of inhomogeneous and anisotropic magnetic fields by polarized neutron grating interferometry
The intrinsic magnetic moment of a neutron, combined with its charge neutrality, is a unique property which allows the investigation of magnetic phenomena in matter. Here we present how the utilization of a cold polarized neutron beam in neutron grating interferometry enables the visualization and characterization of magnetic properties on a microscopic scale in macroscopic samples.
Determining the fate of the Pauling entropy in the classical spin ice material Dy2Ti2O7 with respect to the third law of thermodynamics has become an important test case for understanding the existence and stability of ice-rule states in general. The standard model of spin ice—the dipolar spin ice model—predicts an ordering transition at T ≈ 0.15K, but recent experiments by Pomaranski et al.
Magnetic skyrmions are topologically protected spin-whirls currently considered as promising for use in ultra-dense memory devices. Towards achieving this goal, exploration of the skyrmion phase response and under external stimuli is urgently required.
In a quantum spin liquid, the magnetic moments of the constituent electron spins evade classical long-range order to form an exotic state that is quantum entangled and coherent over macroscopic length scales. Such phases offer promising perspectives for device applications in quantum information technologies, and their study can reveal new physics in quantum matter.