Electric activity at magnetic moment fragmentation in spin ice

TL;DR

This paper explores how magnetic moment fragmentation in spin ice affects electric activity, revealing that partial ordering suppresses electric dipoles and alters electric currents, with implications for controlling magnetic textures via electric fields.

Contribution

It demonstrates that in the moment fragmentation state, electric dipoles become paired and electric activity is reduced, providing new insights into electric-magnetic interplay in spin ice.

Findings

Electric dipoles form pairs in the MF state, reducing electric activity.

Electric currents are significantly influenced by MF in noncoplanar spin systems.

Magnetic textures and excitations exhibit rich behavior modifiable by electric fields.

Abstract

Spin ice systems display a variety of very nontrivial properties, the most striking being the existence in them of magnetic monopoles. Such monopole states can also have nontrivial electric properties: there exist electric dipoles attached to each monopole. A novel situation is encountered in the moment fragmentation (MF) state, in which monopoles and antimonopoles are perfectly ordered, whereas spins themselves remain disordered. We show that such partial ordering strongly modifies the electric activity of such systems: the electric dipoles, which are usually random and dynamic, become paired in the MF state in (d,-d) pairs, thus strongly reducing their electric activity. The electric currents existing in systems with noncoplanar spins are also strongly influenced by MF. We also consider modifications in dipole and current patterns in magnetic textures (domain walls, local defects) and at excitations with nontrivial dynamics in a MF state, which show very rich behaviour and which could in principle allow to control them by electric field.