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Monopolar and dipolar relaxation in spin ice Ho2Ti2O7



Yishu Wang, T. Reeder, Y. Karaki, J. Kindervater, T. Halloran, Nicholas C. Maliszewskyj, Yiming Qiu, Jose Rodriguez Rivera, Sergiy Gladchenko, S. M. Koohpayeh, S. Nakatsuji, Collin L. Broholm


Ferromagnetically interacting Ising spins on the pyrochlore lattice of corner-sharing tetrahedra form a highly degenerate manifold of low-energy states. A spin flip relative to this "spin-ice" manifold can fractionalize into two oppositely charged magnetic monopoles with effective Coulomb interactions. To understand this process, we have probed the low-temperature magnetic response of spin ice to time-varying magnetic fields through stroboscopic neutron scattering and SQUID magnetometry on a new class of ultrapure Ho2Ti2O7 crystals. Covering almost 10 decades of time scales with atomic-scale spatial resolution, the experiments resolve apparent discrepancies between prior measurements on more disordered crystals and reveal a thermal crossover between distinct relaxation processes. Magnetic relaxation at low temperatures is associated with monopole motion through the spin-ice vacuum, while at elevated temperatures, relaxation occurs through reorientation of increasingly spin-like monopolar bound states. Spin fractionalization is thus directly manifest in the relaxation dynamics of spin ice.
Science Advances


monopole dynamics, relaxation, neutron scattering


Wang, Y. , Reeder, T. , Karaki, Y. , Kindervater, J. , Halloran, T. , Maliszewskyj, N. , Qiu, Y. , Rodriguez Rivera, J. , Gladchenko, S. , Koohpayeh, S. , Nakatsuji, S. and Broholm, C. (2021), Monopolar and dipolar relaxation in spin ice Ho2Ti2O7, Science Advances, [online],, (Accessed July 17, 2024)


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Created June 16, 2021, Updated March 25, 2024