%AAnand, Naween%ABarry, Kevin%ANeu, Jennifer%AGraf, David%AHuang, Qing%AZhou, Haidong%ASiegrist, Theo%AChanglani, Hitesh%ABeekman, Christianne%BJournal Name: Nature Communications; Journal Volume: 13; Journal Issue: 1; Related Information: CHORUS Timestamp: 2022-11-24 12:53:04 %D2022%INature Publishing Group %JJournal Name: Nature Communications; Journal Volume: 13; Journal Issue: 1; Related Information: CHORUS Timestamp: 2022-11-24 12:53:04 %K %MOSTI ID: 10368283 %PMedium: X %TInvestigation of the monopole magneto-chemical potential in spin ices using capacitive torque magnetometry %XAbstract

The single-ion anisotropy and magnetic interactions in spin-ice systems give rise to unusual non-collinear spin textures, such as Pauling states and magnetic monopoles. The effective spin correlation strength (Jeff) determines the relative energies of the different spin-ice states. With this work, we display the capability of capacitive torque magnetometry in characterizing the magneto-chemical potential associated with monopole formation. We build a magnetic phase diagram of Ho2Ti2O7, and show that the magneto-chemical potential depends on the spin sublattice (αorβ), i.e., the Pauling state, involved in the transition. Monte Carlo simulations using the dipolar-spin-ice Hamiltonian support our findings of a sublattice-dependent magneto-chemical potential, but the model underestimates theJefffor theβ-sublattice. Additional simulations, including next-nearest neighbor interactions (J2), show that long-range exchange terms in the Hamiltonian are needed to describe the measurements. This demonstrates that torque magnetometry provides a sensitive test forJeffand the spin-spin interactions that contribute to it.

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