7 research outputs found
Magnetic Phases of Rare Earth Hexagonal Manganites
We describe the magnetic phases of hexagonal rare earth manganites RMnO3
using Landau theory. A minimal model based on four one-dimensional magnetic
order parameters is developed.Comment: 2 Pages, Proceedings of SCES'0
Simulations of cubic-tetragonal ferroelastics
We study domain patterns in cubic-tetragonal ferroelastics by solving
numerically equations of motion derived from a Landau model of the phase
transition, including dissipative stresses. Our system sizes, of up to 256^3
points, are large enough to reveal many structures observed experimentally.
Most patterns found at late stages in the relaxation are multiply banded; all
three tetragonal variants appear, but inequivalently. Two of the variants form
broad primary bands; the third intrudes into the others to form narrow
secondary bands with the hosts. On colliding with walls between the primary
variants, the third either terminates or forms a chevron. The multipy banded
patterns, with the two domain sizes, the chevrons and the terminations, are
seen in the microscopy of zirconia and other cubic-tetragonal ferroelastics. We
examine also transient structures obtained much earlier in the relaxation;
these show the above features and others also observed in experiment.Comment: 7 pages, 6 colour figures not embedded in text. Major revisions in
conten
Structural order parameter and itinerant electron magnetism in Cd2Re2O7
We describe the low temperature behaviour of the magnetic susceptibility of
Cd2Re2O7 in terms of a Landau theory of structural phase transitions. We
calculate the zero temperature Pauli susceptibility using a tight-binding
approach to reveal the mechanism of coupling between the structural order
parameter and itinerant magnetism.Comment: Submitted to the Proceedings of ICM 2003, Rom
Superconducting gap nodes in PrOs_4Sb_12
We examine the superconducting gap nodes in crystals with tetrahedral (T_h)
symmetry. The (0,0,1) phase of the three dimensional order parameter in the
triplet channel has nodes in the [001] directions. Following a second order
phase transition to the state (0,i|eta_2|,|eta_1|), each node lifts away from
the Fermi surface and splits into two deep dips. We discuss this scenario in
the context of multiple superconducting phases in PrOs4Sb12.Comment: 2 pages, 1 figure, ICM2006, manuscript with higher quality figure may
be obtained at http://www.physics.mun.ca/~curnoe/papers/PrOs4Sb12.pd
Exotic Heavy Fermion State in the Filled Skutterudite PrFeP Uncovered by the de Haas-van Alphen Effect
We report the de Haas-van Alphen (dHvA) experiment on the filled skutterudite
PrFeP exhibiting apparent Kondo-like behaviors in the transport and
thermal properties. We have found enormously enhanced cyclotron effective mass
in the high field phase (HFP), which
indicates that PrFeP is the first Pr-compound in which really heavy
mass has been unambiguously confirmed. Also in the low field non-magnetic
ordered phase (LOP), we observed the dHvA branch with that is quite heavy taking into account its small Fermi surface volume
(0.15% of the Brillouin zone size). The insensitivity of mass in LOP against
the magnetic field suggests that the quadrupolar interaction plays a main role
both in the mass renormalization and the LOP formation.Comment: 5 pages, 5 figures, Phys. Rev. B (01 October 2002) in pres