Nonmonotonic Zero-Point Entropy in Diluted Spin Ice

Nonmonotonic zero-point entropy in diluted spin ice.

Water ice and spin ice are important model systems in which theory can directly account for "zero-point" entropy associated with quenched configurational disorder. Spin ice differs from water ice in the important respect that its fundamental constituents, the spins of the magnetic ions, can be removed through replacement with nonmagnetic ions while keeping the lattice structure intact. In order...

Anisotropic release of the residual zero-point entropy in the spin ice compound Dy2Ti2O7: Kagome ice behavior

Quantum and thermal spin relaxation in the diluted spin ice Dy2−xMxTi2O7 „M=Lu,Y..

We have studied the low-temperature ac magnetic susceptibility of the diluted spin ice compound Dy2−xMxTi2O7, where the magnetic Dy ions on the frustrated pyrochlore lattice have been replaced with nonmagnetic ions, M =Y or Lu. We examine a broad range of dilutions, 0øxø1.98, and we find that the T ,16 K freezing is suppressed for low levels of dilution but re-emerges for x.0.4 and persists to ...

Finite-temperature transition into a power-law spin phase with an extensive zero-point entropy.

We introduce an xy generalization of the frustrated Ising model on a triangular lattice. The presence of continuous degrees of freedom stabilizes a finite-temperature spin state with power-law discrete spin correlations and an extensive zero-point entropy. In this phase, the unquenched degrees of freedom can be described by a fluctuating surface with logarithmic height correlations. Finite-size...

Spin Waves and Long-Range Order in the Diluted Heisenberg Ferromagnet at Zero Temperature

The variational treatment of spin waves in the randomly diluted Heisenberg ferromagnet at zero temperature is studied. It is argued that a convenient variational principle for the excitation spectrum of an alloy is difficult to formulate rigorously. However, at extremely long wavelengths a simple variational calculatation probably has approximate validity providing localized excitations in isol...