4,300 research outputs found
A Geometrical Model for Stagnant Motion in Hamiltonian Systems with Many Degrees of Freedom
We introduce a model of Poincar\'e mappings which represents hierarchical
structure of phase spaces for systems with many degrees of freedom. The model
yields residence time distribution of power type, hence temporal correlation
remains long. The power law behavior is enhanced as the system size increases.Comment: 6 pages, 3 Encapsulated Postscript figures, LaTeX (58 kb
Effect of strain on the electrical transport and magnetization of the epitaxial Pr0.5Ca0.5MnO3/La0.5Ca0.5MnO3/ Pr0.5Ca0.5MnO3 trilayer structures
Epitaxial trilayer structures consisting of two antifferomagnetic
charge/orbital order insulators Pr0.5Ca0.5MnO3 (PCMO) and La0.5Ca0.5MnO3 (LCMO)
are grown on (001)-oriented SrTiO3 and LaAlO3 substrates. In this trilayer
series, a thin film of LCMO with various thicknesses is sandwiched between the
two fixed thicknesses of PCMO. These samples show a Curie temperature with a
hysteretic field dependent magnetization at 10 K, although the individual
compounds are antiferromagnetic. The zero field electronic transport of all
samples on LAO shows thermally activated behavior, while the thermally
activated behavior is suppressed and a metal-like transport is appearing for
the samples on STO as the LCMO layer thickness increases above 10 unit cell. We
have discussed these magnetic and transport properties of the trilayer
structures on STO and LAO by the interfacial effect due to the stabilized CO
state and the vibration mode of Jahn-Teller distortion.Comment: To be pubslised in Phys. Rev.
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