Pressure Tuned Insulator to Metal Transition in Eu2_2Ir2_2O7_7

We have studied the effect of pressure on the pyrochlore iridate Eu$_2$Ir$_2$O$_7$, which at ambient pressure has a thermally driven insulator to metal transition at $T_{MI}\sim120$\,K. As a function of pressure the insulating gap closes, apparently continuously, near $P \sim 6$\,GPa. However, rather than $T_{MI}$ 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

Optical properties and carrier localization in the layered phosphide EuCd2_\mathbf{2}P2_\mathbf{2}

The temperature dependence of the complex optical properties of the layered phosphide material EuCd$_2$P$_2$ has been measured over a wide frequency range above and below $T_{\rm N} \simeq 11.5$ K for light polarized in the $a-b$ planes. At room temperature, the optical conductivity is well described by a weak free-carrier component with a Drude plasma frequency of $\simeq 1100$ cm$^{-1}$ and a scattering rate of $1/\tau_D\simeq 700$ cm$^{-1}$, with the onset of interband absorptions above $\simeq 2000$ cm$^{-1}$. Two infrared-active $E_u$ modes are observed at $\simeq\,$89 and 239 cm$^{-1}$. As the temperature is reduced the scattering rate decreases and the low-frequency conductivity increases slightly; however, below $\simeq 50$ K the conductivity decreases until at the resistivity maximum at $\simeq 18$ K (just below $2T_{\rm N}$) the spectral weight associated with free carriers is transferred to a localized excitation at $\simeq 500$ cm$^{-1}$. Below $T_{\rm N}$, metallic behavior is recovered. Interestingly, the $E_u$ 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 $\simeq 2T_{\rm N}$ that result in spin-polarized clusters due to spin-carrier coupling [1].Comment: 8 pages with 6 figures; five pages of supplemental materia

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