DW annhilation in wires

Annihilation of domain walls in a ferromagnetic wire.

Anirban Ghosh, Kevin S. Huang, and Oleg Tchernyshyov

Phys. Rev. B 95, 180408(R) (2017)

Several configurations of a pair of domain walls with shown values of separation $\zeta$ and twist $\phi$. The red and blue colors denote positive and negative magnetization component $m_z$ along the axis of the cylinder. The wire frames depict the local plane tangential to the magnetization field. Spheres on the right show the path of the magnetization field $m\left(z\right)$ as $z$ goes from $-\infty$ to $+\infty$, beginning from and ending at the north pole (red). The south pole (blue) can only be reached if the separation of the domain walls $\zeta =\infty$.

Effect of volume distribution broadenig in properties of NPs

Magnetic properties of nanoparticle compacts with controlled broadening of the particle size distribution.

M. S. Andersson, R. Mathieu, P. S. Normile, S. S. Lee, G. Singh, P. Nordblad, and J. A. De Toro

Phys. Rev. B 95, 184431 (2017)

(a) Low-field (800 A/m) ZFC/FC M/H vs $T$ curves for MIX0 and a diluted sample from the same nanoparticle batch (reference MIX0). M/H values are normalized to the maximum of their ZFC M/H curves. (b) In-phase (${\chi }^{\prime }$) and (c) out-of-phase (${\chi }^{\text{'}\text{'}}$) components of the ac susceptibility as a function of the temperature ($f=10$ Hz) for selected compacts as in the legend in (c). Inset in (b): Temperature of the maximum of the in-phase susceptibility ($T_{\max }$) as a function of the concentration of 11.5-nm particles.