283 research outputs found
Optical properties and carrier localization in the layered phosphide EuCdP
The temperature dependence of the complex optical properties of the layered
phosphide material EuCdP has been measured over a wide frequency range
above and below K for light polarized in the
planes. At room temperature, the optical conductivity is well described by a
weak free-carrier component with a Drude plasma frequency of
cm and a scattering rate of cm, with the
onset of interband absorptions above cm. Two
infrared-active modes are observed at 89 and 239 cm. As
the temperature is reduced the scattering rate decreases and the low-frequency
conductivity increases slightly; however, below K the conductivity
decreases until at the resistivity maximum at K (just below
) the spectral weight associated with free carriers is transferred
to a localized excitation at cm. Below ,
metallic behavior is recovered. Interestingly, the modes are largely
unaffected by these changes, with only the position of the high-frequency mode
showing any signs of anomalous behavior. While several scenarios are
considered, the prevailing view is that the resistivity maximum and subsequent
carrier localization is due to the formation of ferromagnetic domains below
that result in spin-polarized clusters due to spin-carrier
coupling [1].Comment: 8 pages with 6 figures; five pages of supplemental materia
Pressure Tuned Insulator to Metal Transition in EuIrO
We have studied the effect of pressure on the pyrochlore iridate
EuIrO, which at ambient pressure has a thermally driven insulator
to metal transition at \,K. As a function of pressure the
insulating gap closes, apparently continuously, near \,GPa. However,
rather than going to zero as expected, the insulating ground state
crosses over to a metallic state with a negative temperature coefficient of
resistivity, calling into question the true nature of both ground states. The
high temperature state also crosses over near 6 GPa, from an incoherent to a
conventional metal, suggesting a connection between the high and the low
temperature states.Comment: 7 pages, 7 figures, updated after publication in Physical Review
Determining infertility treatment costs and out of pocket payments imposed on couples
Background: Infertility and infertility treatment costs are considered as one of the main challenges that human society increasingly face with.Objective: To determine infertility treatment costs and out of pocket expenditures imposed on couples referred to infertility treatment center in Yazd, Iran.Design: A descriptive cross sectional studySubjects: A total of 216 couples were selected and contributed in the study through convenient sampling method.Setting: Telephone interviews with couples and medical documents review were also used to ensure the accuracy of collected information.Results: Lost opportunity, direct and indirect costs were 5.562.526, 37.812.354 and 11.125.395 rial respectively (1USD=33,000 rial). Among direct costs the most and the least expenditures belonged to surgery (24.042.137 rial) and clinical visits (174.053 rial). The greatest portion of indirect costs was related to accommodation expenses and the least was due to travel costs (4.898.099 and 2.738.491 rial). Findings confirmed a significant statistical relation between indirect costs and patients’ living place, also a significant relation between lost opportunity cost and patients’ occupation (P<0.05).Conclusion: Due to the high expenditures related to infertility treatment services also lack of insurance coverage, policy makers should pay a particular attention on meeting the reproductive health needs of a society
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