270 research outputs found
Role of Orbital Degeneracy in Double Exchange Systems
We investigate the role of orbital degeneracy in the double exchange (DE)
model. In the limit, an effective generalized ``Hubbard''
model incorporating orbital pseudospin degrees of freedom is derived. The model
possesses an exact solution in one- and in infinite dimensions. In 1D, the
metallic phase off ``half-filling'' is a Luttinger liquid with
pseudospin-charge separation. Using the solution for our effective
model, we show how many experimental observations for the well-doped () three-dimensional manganites can be qualitatively
explained by invoking the role of orbital degeneracy in the DE model.Comment: 8 pages, 2 figures, submitted to Phys. Rev.
Specific heat study of single crystalline Pr Ca MnO in presence of a magnetic field
We present the results of a study of specific heat on a single crystal of
PrCaMnO performed over a temperature range 3K-300K in
presence of 0 and 8T magnetic fields. An estimate of the entropy and latent
heat in a magnetic field at the first order charge ordering (CO) transition is
presented. The total entropy change at the CO transition which is 1.8
J/mol K at 0T, decreases to 1.5 J/mol K in presence of 8T magnetic
field. Our measurements enable us to estimate the latent heat
235 J/mol involved in the CO transition. Since the entropy of the
ferromagnetic metallic (FMM) state is comparable to that of the charge-ordered
insulating (COI) state, a subtle change in entropy stabilises either of these
two states. Our low temperature specific heat measurements reveal that the
linear term is absent in 0T and surprisingly not seen even in the metallic FMM
state.Comment: 8 pages (in RevTEX format), 12 figures (in postscript format)
Submitted to Phys. Rev.
Anisotropic phonon conduction and lattice distortions in CMR-type bilayer manganite (LaPr)SrMnO (z=0,0.2,0.4 and 0.6) single crystals
We have undertaken a systematic study of thermal conductivity as a function
of temperature and magnetic field of single crystals of the compound
(LaPr)SrMnO for (Pr) =0.2,0.4. and
0.6. The lattice distortion due to Pr-substitution and anisotropic thermal
conductivity in bilayer manganites are discussed on the basis of different
relaxation models of local lattice distortions in metal and insulating states
proposed by Maderda et al. The giant magnetothermal effect is scaled as a
function of magnetization and discussed on the basis of a systematic variation
of the occupation of the -electron orbital states due to Pr-substitution.Comment: 7 pages, 6 figures, in press in Phys.Rev.
Phase Transition in Perovskite Manganites with Orbital Degree of Freedom
Roles of orbital degree of freedom of Mn ions in phase transition as a
function of temperature and hole concentration in perovskite manganites are
studied. It is shown that the orbital order-disorder transition is of the first
order in the wide region of hole concentration and the Nel
temperature for the anisotropic spin ordering, such as the layer-type
antiferromagnetic one, is lower than the orbital ordering temperature due to
the anisotropy in the orbital space. The calculated results of the temperature
dependence of the spin and orbital order parameters explain a variety of the
experiments observed in manganites.Comment: 10 pages, 5 figure
Structural analysis of the Ss sialoglycoprotein specific for Henshaw blood group from human erythrocyte membranes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66122/1/j.1432-1033.1984.tb08155.x.pd
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International experience and FDI location choices of Chinese firms: The moderating effects of home country government support and host country institutions
We examine the extent to which Chinese government support of foreign direct investment (FDI) projects and host country institutional environments interact with prior entry experience by Chinese firms, and how this interrelationship affects FDI undertaken by Chinese firms. We hypothesize that home country government support and well-established host country institutions enhance organizational capabilities to take risks in FDI. As such, they reduce the need to accumulate experiential knowledge and capabilities relating to entering host countries based on prior entry experience in a particular country when undertaking follow-up investment projects. Using a unique, hand-collected panel data set of Chinese publicly listed firms during 2002–2009, we find that home government support and well-developed host country institutions reduce the importance of prior entry experience and significantly increase the likelihood of FDI entry into a host country. Further, from our subsample analyses we identify differences between entering developed and developing host countries in terms of the impact of home country government support and quality of host country institutions. Our findings help explain the puzzle concerning why emerging economy firms have rapidly internationalized in a short period of time and do not follow the pattern predicted by classical IB theories
Corruption and its effects on FDI:Analysing the interaction between the corruption levels of the home and host countries and its effects at the decision-making level
This study furthers our understanding of how corruption affects the decision-making process of allocating foreign direct investment. Drawing on the responses of 28 managers in charge of establishing operations in a highly corrupt host country, we argue that those firms based in home countries with low levels of corruption are more proactive in preparing to face corruption abroad than those based in countries with high corruption levels. This means that firms from less corrupt home countries have strategies in place to deal with high corruption abroad. This finding is based on the fact that these firms have stronger pressures to not engage in corruption from their home stakeholders. Also, these firms might not have the experience of dealing with corruption at home, which hinders their potential to deal with corruption abroad. On the other hand, those firms based in highly corrupt home countries do not have clear strategies to deal with corruption abroad. This assertion is based on the fact that these firms might have familiarity in dealing with corruption and thus, might not see it as an obstacle to operating abroad
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