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We classified fabrics of 851 horizons of Canadian soils, according to Brewer's (1979) system, and related them to particle size, organic matter content, and kind of horizon. Relationships between related distribution of fine and coarse particles and particle size were much less evident for Canadian soils than for Australian soils studied by Brewer. Reasons for this might be the markedly higher silt contents and the generally higher organic matter contents of the Canadian soils. Fabrics of most of the samples studied were porphyric, and more than 90 percent of the samples with porphyric fabrics contained more than 40 percent silt plus clay. For samples with less than 40 percent silt plus clay, consideration of the kind of genetic horizon, in addition to particle size, increased the predictability of soil fabric.

The variation of the electrical resistanceR of EuMo6S8 with temperatureT and applied magnetic fieldH was determined at pressuresP to 19 kbar. At ambient pressure, the results are in agreement with previous work on samples of similar quality, where it was determined that variations of the carrier concentration were responsible for the very strong dependence ofR onT andH. AtP=8.5 kbar, the magnetoresistance is determined by the freezing out of the Eu2+ spins asH increases. ForP>13 kbar, EuMo6S8 exhibits bulk superconductivity, and we investigated the upper critical magnetic fieldHc2(T). The analysis of these results shows that our EuMo6S8 samples are clean superconductors. We observe thatHc2 is strongly reduced by pressure, perhaps due to an increase of the carrier concentration with pressure.

The effect of hydrostatic pressure on the superconductivity of La1.2-xEuxMo6S8 pseudoternary compounds was studied by means of low-frequency ac and dc magnetic susceptibility measurements up to 20 kbar. The superconducting transition temperatureTc at ambient pressure is a weak function of Eu concentrationx for 0?x?0.2, and then decreases smoothly withx forx>0.2 until superconductivity is completely suppressed forx=0.95. Pressure was found to decreaseTc in the La-rich compounds and to increaseTc in the Eu-rich compounds. Pressure also induces superconductivity in compounds withx>0.95 that are not superconducting at ambient pressure. A La0.2Eu1.0Mo6S8 compound revealed a sizeable Meissner effect for pressures larger than 7 kbar.

Finely ground powders ofRBa2Cu3O7 - d (R=Y, Nd, Sm, Eu, Dy, Ho, Er, Tm, Yb) have been mixed at dilute 3%-by-volume concentrations into epoxy matrices which were then allowed to harden in applied magnetic fieldsHA=18 kOe. X-ray diffractometry studies and 4.3 K measurements of supercurrent-induced magnetization hysteresis?M are interpreted as indicating at least partial alignment of single-crystal-grain c-axes (1) parallel toHA forR=Y, Nd, Sm, Dy, Ho (as earlier found by Farrell et al. forR=Y), and (2) perpendicular toHA forR=Eu, Er, Tm, Yb. With a few exceptions (Y, Sm, Eu) the alignment direction correlates with the sign of the second-order Stevens factoraJ of the crystalline electric field Hamiltonian in the manner suggested by Livingston et al. For the best aligned specimens (Ho, Dy) critical current densitiesJc (4.3 K, 5 kOe) for individual grains are estimated from?M and the Bean model to be of order 107 A/cm2 for the measuring fieldH parallel to the original alignment fieldHA, and of order 106 A/cm2 forH perpendicular toHA.

Investigations of Y1-xMxBa2Cu3O7-d (M=Ce, Th)c-axis oriented thin film specimens show that the rate of depression ofTc withx is larger for M=Th, than for M=Ce and Pr, and suggest that Ce, like Th, is tetravalent in this compound. Hall effect measurements on Y1-xPrxBa2Cu3O7-d single crystals reveal aT2 dependence of the cotangent of the Hall angle in the normal state and a “negative Hall anomaly” belowTc in the superconducting state, in agreement with recent reports. Our research shows that the depth, ?, of the negative Hall signal scales withT/Tc and that the maximum value of ? decreases linearly withx and vanishes atx˜0.24. Magnetoresistance measurements on Y1-xPrxBa2Cu3O7-d single crystals indicate that the irreversibility lineH(T*) obeys a universal scaling relation characterized by anm=3/2 power law nearTc, with a crossover to a more rapid temperature dependence of belowT/Tc˜0.6, similar to that observed for polycrystalline specimens.

The temperature and Zn concentration dependence of the electrical resistivity, specific heat, magnetic susceptibility, and electron paramagnetic resonance (EPR) spectra of YBa2(Cu1-xZnx)3O7-y withy~0.1 has been measured forx=0.16. In addition, the temperature and field dependence of the magnetization has been measured for 22Cu3O7-y causes a rapid and nearly linear depression of the superconducting transition temperature,Tc, withTc going to 0 K forx= 0.10. YBa2(Cu1-xZnx)3O7-y retains the YBa2Cu3O7-y orthorhombic structure forx=0.16 for both the superconducting and nonsuperconducting samples. Initially, the unit cell volume increases nearly linearly with Zn content; however, an abrupt change occurs in the vicinityx=0.8–0.10. Forx<0.10, the temperature dependence of the electrical resistivity,?(T), is metallic-like (d?/dT>0) and? increases gradually with increasing Zn content. However, forx= 0.10,?(T) becomes semiconductor-like, with a very rapid increase of the resistivity with increasingx. The electrical resistivity, magnetic susceptibility, EPR spectra, and specific heat all indicate that thed-holes associated with the Cu ions become localized in the nonsuperconducting phase,x>-0.10.

Estimates by 10 operators of illuvial clay in thin sections of six B horizons differed widely; coefficients of variation ranged from 39 to 64 percent. The results cast serious doubt on the usefulness of oriented, apparently illuvial, clay in thin sections as a quantitative criterion of argillic horizons unless steps are taken to ensure a greater degree of uniformity of estimates.

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