1.1 Spin Ices
3
a
b
Fig. 1.2 (a) Structure of water ice consists of an oxygen atom (blue) at the center of a tetrahedron
with two hydrogens (grey) bound close to the oxygen and two hydrogens sitting away from the
oxygen, (b) Spin Ice configuration of Dy 2 Ti 2 O 7 where two Dy spins point into the center of the
tetrahedron and two Dy spins point out; this is similar to structure of water ice
Fig. 1.3 Top left: Specific heat C(T ) measurements of Dy 2 Ti 2 O 7 show a lack of an ordering
feature when the compound is in zero field. Bottom left: The residual spin entropy of Dy 2 Ti 2 O 7
is shown in this plot. Reprinted by permission from [Springer Nature Customer Service Centre
GmbH]: [Nature] [10] (Zero-point entropy in ‘spin ice’, Ramirez et al.), [©] (1999). Right: Sharp
peaks in the specific heat of Dy 2 Ti 2 O 7 appear when strong magnetic fields are applied. Figure
reproduced with permission from from Ref. [11]. ©(2004) The Physical Society of Japan
3
a
b
Fig. 1.2 (a) Structure of water ice consists of an oxygen atom (blue) at the center of a tetrahedron
with two hydrogens (grey) bound close to the oxygen and two hydrogens sitting away from the
oxygen, (b) Spin Ice configuration of Dy 2 Ti 2 O 7 where two Dy spins point into the center of the
tetrahedron and two Dy spins point out; this is similar to structure of water ice
Fig. 1.3 Top left: Specific heat C(T ) measurements of Dy 2 Ti 2 O 7 show a lack of an ordering
feature when the compound is in zero field. Bottom left: The residual spin entropy of Dy 2 Ti 2 O 7
is shown in this plot. Reprinted by permission from [Springer Nature Customer Service Centre
GmbH]: [Nature] [10] (Zero-point entropy in ‘spin ice’, Ramirez et al.), [©] (1999). Right: Sharp
peaks in the specific heat of Dy 2 Ti 2 O 7 appear when strong magnetic fields are applied. Figure
reproduced with permission from from Ref. [11]. ©(2004) The Physical Society of Japan