24,469 research outputs found
Conversion of glassy antiferromagnetic-insulating phase to equilibrium ferromagnetic-metallic phase by devitrification and recrystallization in Al substituted PrCaMnO
We show that PrCaMnO with 2.5% Al substitution and
LaCaMnO (LCMO) exhibit qualitatively similar and
visibly anomalous M-H curves at low temperature. Magnetic field causes a broad
first-order but irreversible antiferromagnetic (AF)-insulating (I) to
ferromagnetic (FM)-metallic (M) transition in both and gives rise to soft FM
state. However, the low temperature equilibrium state of
PrCaMnAlO (PCMAO) is FM-M whereas that
of LCMO is AF-I. In both the systems the respective equilibrium phase coexists
with the other phase with contrasting order, which is not in equilibrium, and
the cooling field can tune the fractions of the coexisting phases. It is shown
earlier that the coexisting FM-M phase behaves like `magnetic glass' in LCMO.
Here we show from specially designed measurement protocols that the AF-I phase
of PCMAO has all the characteristics of magnetic glassy states. It devitrifies
on heating and also recrystallizes to equilibrium FM-M phase after annealing.
This glass-like AF-I phase also shows similar intriguing feature observed in
FM-M magnetic glassy state of LCMO that when the starting coexisting fraction
of glass is larger, successive annealing results in larger fraction of
equilibrium phase. This similarity between two manganite systems with
contrasting magnetic orders of respective glassy and equilibrium phases points
toward a possible universality.Comment: Highlights potential of CHUF (Cooling and Heating in Unequal Fields),
a new measurement protoco
3-D inelastic analysis methods for hot section components. Volume 2: Advanced special functions models
This Annual Status Report presents the results of work performed during the third year of the 3-D Inelastic Analysis Methods for Hot Sections Components program (NASA Contract NAS3-23697). The objective of the program is to produce a series of computer codes that permit more accurate and efficient three-dimensional analyses of selected hot section components, i.e., combustor liners, turbine blades, and turbine vanes. The computer codes embody a progression of mathematical models and are streamlined to take advantage of geometrical features, loading conditions, and forms of material response that distinguish each group of selected components
Three-dimensional inelastic analysis for hot section components, BEST 3D code
The goal is the development of an alternative stress analysis tool, distinct from the finite element method, applicable to the engineering analysis of gas turbine engine structures. The boundary element method was selected for this development effort on the basis of its already demonstrated applicability to a variety of geometries and problem types characteristic of gas turbine engine components. Major features of the BEST3D computer program are described, and some of the significant developments carried out as part of the Inelastic Methods Contract are outlined
Statistical mechanics of confined quantum particles
We develop statistical mechanics and thermodynamics of Bose and Fermi systems
in relativistic harmonic oscillator (RHO) confining potential, which may be
applicable in quark gluon plasma (QGP), astrophysics, Bose-Einstein
condensation (BEC), condensed matter physics etc. Detailed study of QGP system
is carried out and compared with lattice results. Further, as an application,
our equation of state (EoS) of QGP is used to study compact stars like quark
star.Comment: 9 pages, 2 figures, articl
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