Domains, domain walls and the coercive field of amorphous ferromagnets

Barkhausen avalanches in anisotropic ferromagnets with 180° domain wall

We show that Barkhausen noise in two-dimensional disordered ferromagnets with extended domain walls is characterized by the avalanche size exponent ts51.54 at low disorder. With increasing disorder the characteristic domain size is reduced relative to the system size due to nucleation of new domains and a dynamic phase transition occurs to the scaling behavior with ts51.30. The exponents decrea...

Combined effects of magnetic interaction and domain wall pinning on the coercivity in a bulk Nd60Fe30Al10 ferromagnet

Understanding the coercivity mechanism has a substantial impact on developing novel permanent materials. However, the current coercivity mechanisms used widely in permanent alloys cannot explain well the amorphous phase produced hard magnetic behavior of Nd-based bulk amorphous alloys (BAAs). Here, we propose that the coercivity in as-cast Nd60Fe30Al10 alloy is from the combination of magnetic ...

Néel-like domain walls in ferroelectric Pb(Zr,Ti)O3 single crystals

In contrast to the flexible rotation of magnetization direction in ferromagnets, the spontaneous polarization in ferroelectric materials is highly confined along the symmetry-allowed directions. Accordingly, chirality at ferroelectric domain walls was treated only at the theoretical level and its real appearance is still a mystery. Here we report a Néel-like domain wall imaged by atom-resolved ...

Dirac electrons and domain walls: A realization in junctions of ferromagnets and topological insulators

Intrinsic ferroelectric switching from first principles.

The existence of domain walls, which separate regions of different polarization, can influence the dielectric, piezoelectric, pyroelectric and electronic properties of ferroelectric materials. In particular, domain-wall motion is crucial for polarization switching, which is characterized by the hysteresis loop that is a signature feature of ferroelectric materials. Experimentally, the observed ...