Magnetic Coulomb phase in the spin ice Ho2Ti2O7.
Spin-ice materials are magnetic substances in which the spin directions map onto hydrogen positions in water ice. Their low-temperature magnetic state has been predicted to be a phase that obeys a Gauss' law and supports magnetic monopole excitations: in short, a Coulomb phase. We used polarized neutron scattering to show that the spin-ice material Ho2Ti2O7 exhibits an almost perfect Coulomb phase. Our result proves the existence of such phases in magnetic materials and strongly supports the magnetic monopole theory of spin ice.
Fennell
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Institut Laue-Langevin, Grenoble 38042, France. fennell@ill.fr
Deen
P P
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Wildes
A R
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Schmalzl
K
K
Prabhakaran
D
D
Boothroyd
A T
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Aldus
R J
RJ
McMorrow
D F
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Bramwell
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