A Frustrated Antipolar Phase Analogous to Classical Spin Liquids.

The study of magnetic frustration in classical spin systems is motivated by the prediction and discovery of classical spin liquid states. These uncommon magnetic phases are characterized by a massive degeneracy of their ground state implying a finite magnetic entropy at zero temperature. While the classical spin liquid state is originally predicted in the Ising triangular lattice antiferromagnet in 1950, this state has never been experimentally observed in any triangular magnets.

Proton dynamics in superprotonic RbH(SeO)crystal by broadband dielectric spectroscopy.

Broadband dielectric and AC conductivity spectra (1 Hz to 1 THz) of the superprotonic single crystal RbH(SeO)(RHSe) along theaxis were studied in a wide temperature range 10 K << 475 K that covers the ferroelastic (< 453 K) and superprotonic (> 453 K) phases. A contribution of the interfacial electrode polarization layers was separated from the bulk electrical properties and the bulk DC conductivity was evaluated above room temperature. The phase transition to the superprotonic phase was shown to be connected with the steep but almost continuous increase in bulk DC conductivity, and with giant permittivity effects due to the enhanced bulk proton hopping and interfacial electrode polarization layers.

Broadband dielectric spectroscopy of LaSrMnO@TiOcore-shell nanocomposites.

Core-shell composites of ferromagnetic conducting nanoparticles LaSrMnO(LSMO) embedded in an insulating matrix of TiO(LSMO@TiO) have been processed, structurally and magnetically characterized, and their DC magnetoresistivity and complex dielectric response measured and fitted from Hz up to the infrared (IR) range (10Hz). XRD indicates that the TiOshells are amorphous. Modelling of the IR spectra using standard models based on the effective medium approximation has it confirmed and has characterized the effective phonon modes of the LSMO nanoceramics and LSMO@TiOcomposite.