679 research outputs found
Thermodynamic properties of quadrupolar states in the frustrated pyrochlore magnet TbTiO
The low-temperature thermodynamic properties of the frustrated pyrochlore
TbTiO have been studied using the single crystal of
sitting in a long range ordered phase in the - phase diagram.
We observed that the specific heat exhibits a minimum around 2 K and slightly
increases on cooling, similar to a Schottky-like anomaly for canonical spin
ices. A clear specific-heat peak observed at K is ascribable
to the phase transition to a quadrupolar state, which contributes to a
relatively large change in entropy, J Kmol.
However, it is still smaller than for the ground state doublet of the
Tb ions. The entropy release persists to higher temperatures, suggesting strong
fluctuations associated with spin ice correlations above . We
discuss the field dependence of the entropy change for and
.Comment: 6 pages, 2 figure
Singlet-triplet Crossover in the Two-dimensional Dimer Spin System YbAl3C3
Low-temperature magnetization (M) measurements down to 0.1 K have been
performed in magnetic fields up to 14.5 T for a single piece of a tiny
single-crystalline sample (0.2 mg weight) of the spin-gap system YbAl3C3. At
the base temperature of 0.1 K, several metamagnetic transitions were clearly
observed for H // c in the range 6 T < H < 9 T whereas only two transitions
were observed, one at 4.8 T and the other at 6.6 T, for H // a. At fields above
9 T, the magnetization becomes almost saturated for both H // a and H // c. The
present results indicate that a singlet-triplet crossover occurs in a
relatively narrow field range, suggesting a rather weak interdimer interaction
in spite of the nearly triangular lattice of Yb ions.Comment: 5 pages, 6 figures, proceedings of ICM 201
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