The applicability of Nkel's pair model to metallic 3d surfaces and interfaces is explained in terms of the tight-binding momentstheorem. The Nee1 model reproduces itinerant magnetism so long as the band structure is approximated by third-moment atomic-pair contributions. This establishes an atomic NCel description of interfaces and impurities. The NCel parameter g depends on the d-band filling ...

Muon spin relaxation measurements in iron-oxypnictide systems have revealed: (1) commensurate long-range order in undoped LaFeAsO; (2) a Bessel function line shape in LaFeAs(O0.97F0.03) which indicates possible incommensurate or stripe magnetism; (3) anomalous weak magnetism existing in superconducting LaFePO, CeFeAs(O0.084F0.16), and NdFeAs(O0.88F0.12) but absent in superconducting LaFeAs(O0.9...

M a g n e t i c f i e l d s a r e u b i q u i t o u s i n t h e U n i v e r s e b e c a u s e o f t h e a b s e n c e (o r r a r i t y ) o f f r e e m a g n e t i c m o n o p o l e s . However , t h e l a r g e s c a l e c o n c e n t r a t i o n of m a g n e t i c f l u x i n an e s s e n t i a l l y n o n f e r r o m a g n e t i c body s u c h a s t h e E a r t h , r e q u i r e s a n o n c o...

An isolated classical chaotic system, when driven by the slow change in several parameters, responds with two reaction forces: geometric friction and geometric magnetism. By using the theory of quantum fluctuation relations, we show that this holds true also for open quantum systems and provide explicit expressions for those forces in this case. This extends the concept of Berry curvature to th...

When electrons are driven through unconventional magnetic structures, such as skyrmions, they experience emergent electromagnetic fields that originate several Hall effects. Independently, ground-state emergent magnetic fields can also lead to orbital magnetism, even without the spin-orbit interaction. The close parallel between the geometric theories of the Hall effects and of the orbital magn...

Multiferroics are materials that simultaneously exhibit more than one ferroic order parameters, such as ferroelectricity, ferroelasticity and ferromagnetism. Recently, multiferroicity has received a significant revival of interest due to the colossal magnetoelectric coupling effect for the development of nano-ferronics. In this mini-review, we focus on a recent study of ferroelectricity, magnet...

We study a model of a d-wave superconductor with strong potential scatterers in the presence of antiferromagnetic correlations and apply it to experimental nuclear magnetic resonance NMR results on Zn impurities in the superconducting state of YBa2Cu3O7− . We then focus on the contribution of impurity-induced paramagnetic moments, with Hubbard correlations in the host system accounted for in Ha...

The effect of spin-orbit interaction on persistent currents in mesoscopic Hubbard rings threaded by an Aharonov-Bohm flux is investigated putting stress on the orbital magnetism. The non-perturbative treatment of the spin-orbit interaction developed by Meir et al. is combined with the Bethe ansatz solution to deal with this problem exactly. We find that the interplay of spin-orbit interaction a...

In this study, we use evidence from students in grades 10-12 (N = 138) to document the ways in which children learn about and model their conceptual understanding of magnetism. Our model-based design capitalizes on phenomena that are engaging to students, to describe the behavior of magnetic materials across scale, from the familiar to the nanoscale. Data are drawn from written responses to pre...

We study from first principles the magnetism in graphene induced by single carbon atom defects. For two types of defects considered in our study, the hydrogen chemisorption defect and the vacancy defect, the itinerant magnetism due to the defect-induced extended states has been observed. Calculated magnetic moments are equal to 1 B per hydrogen chemisorption defect and 1.12–1.53 B per vacancy d...