Search

Magneto-transport properties of single crystal SnSe thermoelectric

Thin Al x Mo 100− x films (40 ≤ x ≤ 90 with x in steps of 5 at % Al) were prepared by magnetron co-deposition onto alumina, glass, and saphire substrates at room temperature. The film thickness was about 400 nm, and they were amorphous for 45 ≤ x ≤ 85. The films' structural changes upon heating were investigated by measurement of the electrical resistivity variation with temperature, ρ (T), during the isochronal heating. Thus obtained results were complemented, and conclusions confirmed, by GIXRD analysis for selected heating temperatures. The dynamical temperatures of crystallization, T x , were determined from the sharp increase of the derivative of ρ with respect to temperature. No systematic dependence of T x on film substrate has been observed. Except for the Al 85 Mo 15 film, the ρ of the amorphous films increase on the crystallization. The temperature of crystallization exhibits maximum around 530 °C for alloy compositions with x = 55 and 60. Electrical resistivity of both amorphous and crystallized films show a strong dependence on alloy composition, with a maximum for Al 75 Mo 25 alloy. The resistivity of Al 75 Mo 25 film is very large and amounts to 1000 μΩ cm and 3000 μΩ cm in amorphous and crystallized film, respectively, with the large negative temperature coefficient of −10 × 10 −4 K −1 and −14 × 10 −4 K −1 , respectively. Although the crystallization temperature observed for the examined amorphous Al–Mo alloys is not very high, it might allow to exploit excellent corrosion properties of such films at some elevated temperatures.

Low temperature transport properties of single crystal SnSe thermoelectric

The intermetallic phase InPd is a candidate material for the use as a catalyst in the methanol steam reforming process. To study the connection between the catalytic properties of the surface and the structural and electronic properties of the bulk, we have grown single crystals of the InPd phase by the Czochralski method and determined their electronic, thermal, magnetic and hydrogen-absorption properties. By growing crystals from a high-temperature solution, we could crystallize a slightly offstoichiometric In-rich composition In1.04Pd0.96, which contained a significant amount of constitutional defects in the lattice (Pd vacancies on the Pd sublattice) to retain the CsCl-type structure. The strongly inhomogeneously broadened 115 In NMR spectrum and the high residual (T / 0) electrical resistivity confirmed the presence of constitutional defects. Single crystals of InPd do not absorb hydrogen, as requested for a good hydrogenation catalyst material. Calculated electronic density of states (DOS) shows large contribution of Pd(d) states at the Fermi level. Application of the electron localizability indicator reveals ionic and multi-centre InePd interactions stabilizing the crystal structure. The electrical and thermal conductivities of InPd show metallic character, whereas the thermoelectric power and the Hall coefficient both show positive sign, revealing that InPd is a predominant hole-type conductor. The calculated electronic DOS at the Fermi energy is in a good agreement with the experimental value determined from the low-temperature specific heat. Magnetic measurements have shown that InPd is a diamagnet. All results are compared to the chemically related intermetallic compound GaPd. The active esite-isolation concept for increased catalytic selectivity is discussed in relation to the InPd and GaPd structures.

Drug prescribing and referrals to specialists’ consultations, as the indicators of the quality of health care, were not so often monitored in Croatian family medicine. The aims of the study are to determine the trends of referrals from family doctors to specialists’ consultations and the trends of specialists’ consultations utilization. The study is based on routinely collected data from the Croatian Health Service Yearbooks, 1995–2012. The results indicate that from 1995 to 2012 the visits to family doctors almost doubled, while the number of referrals increased by 60%. The referral rate only slightly increased, from 24 to 29% of the total number of visits. The number of specialists’ consultations showed continuous growth and exceeded the number of referrals. The observed trends are not sufficient to explain referral patterns and utilization of specialists’ services; therefore, a far more complex research is required.