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تسجيل مستخدم جديدUniversal dynamics of magnetic monopoles in two-dimensional kagom{e} ice
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A magnetic monopole in spin ice is a novel quasiparticle excitation in condensed matter physics, and we found that the ac frequency dependent magnetic susceptibility $chi(omega)$ in the two-dimensional (2D) spin ice (so-called kagom{e} ice) of Dy$_2$Ti$_2$O$_7$ shows a single scaling form. This behavior can be understood in terms of the dynamical scaling law for 2D Coulomb gas (CG) systems [Phys. Rev. B 90, 144428 (2014)], characterized by the charge correlation length $xi (propto1/sqrt{omega_1})$, where $omega_{1}$ is a characteristic frequency proportional to the peak position of the imaginary part of $chi(omega)$. It is a generic behavior among a wide variety of models such as the vortex dynamics of 2D superconductors, 2D superfluids, classical XY magnets, and dynamics of melting of Wigner crystals.
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While sources of magnetic fields - magnetic monopoles - have so far proven elusive as elementary particles, several scenarios have been proposed recently in condensed matter physics of emergent quasiparticles resembling monopoles. A particularly simp
le proposition pertains to spin ice on the highly frustrated pyrochlore lattice. The spin ice state is argued to be well-described by networks of aligned dipoles resembling solenoidal tubes - classical, and observabl
One of the most remarkable examples of emergent quasi-particles, is that of the fractionalization of magnetic dipoles in the low energy configurations of materials known as spin ice, into free and unconfined magnetic monopoles interacting via Coulomb
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Artificial spin ice offers the possibility to investigate a variety of dipolar orderings, spin frustrations and ground states. However, the most fascinating aspect is the realization that magnetic charge order can be established without spin order. W
e have investigated magnetic dipoles arranged on a honeycomb lattice as a function of applied field, using magnetic force microscopy. For the easy direction with the field parallel to one of the three dipole sublattices we observe at coercivity a maximum of spin frustration and simultaneously a maximum of charge order of magnetic monopoles with alternating charges $pm$ 3.
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