Geology topics

T. Pankey

Publications and source records attributed to T. Pankey.

4 recordsLinked to original sources

USGS1963

Antiferromagnetism of UO2⋅2H2O

Magnetic susceptibility measurements have been made on UO 2 · x H 2 O for x =1.78 to x =2.13, and from 77° to 375°K. As the value of x decreased the susceptibility increased. Both these data and structural arguments imply that the formula of this compound is U(OH) 4 rather than the dihydrate form. Based on this concept the data have been corrected for diamagnetism and also small amounts of UO 2 and H 2 O which were present. The molar susceptibility of U 4+ in U(OH) 4 is nearly an order of magnitude less than in other uranium compounds, and it is suggested that this is probably due to superexchange between adjacent uranium atoms through intervening oxygen atoms.

Journal of Chemical Physics↗

USGS1960

Magnetic susceptibility of tetragonal titanium dioxide

Careful measurements have been made of the magnetic susceptibility of the rutile and anatase crystalline forms of titanium dioxide. The magnetic susceptibility of a single crystal of high-purity rutile was found to be (0.067±0.0015)× 10 − 6 emu per gram, and was temperature-independent from 55° to 372°K. Difficulty was encountered in obtaining a good value of the magnetic susceptibility of anatase because of impurities. However, a value of 0.02× 10 − 6 emu per gram was obtained as a maximum value for anatase powder. A discussion is given for the different values obtained for anatase and rutile.

Physical Review↗

USGS1960

Anisotropy of the magnetic susceptibility of gallium

The bulk magnetic susceptibilities of single gallium crystals and polycrystalline gallium spheres were measured at 25°C. The following anisotropic diamagnetic susceptibilities were found: a axis (−0.119±0.001)×10 −6 emu/g, b axis (−0.416±0.002)×10 −6 emu/g, and c axis (−0.229±0.001) emu/g. The susceptibility of the polycrystalline spheres, assumed to be the average value for the bulk susceptibility of gallium, was (−0.257±0.003)×10 −6 emu/g at 25°C, and (−0.299±0.003)×10 −6 emu/g at −196°C. The susceptibility of liquid gallium was (0.0031±0.001)×10 −6 emu/g at 30°C and 100°C. Rotational diagrams of the susceptibilities in the three orthogonal planes of the unit cell were not sinusoidal. The anisotropy in the single crystals was presumably caused by the partial overlap of Brillouin zone boundaries by the Fermi‐energy surface. The large change in susceptibility associated with the change in state was attributed to the absence of effective mass influence in the liquid state.

Journal of Applied Physics↗

USGS1958

Quartz helix magnetic susceptibility balance using the Curie-Cheneveau principle

A quartz spring balance is described which can be used to measure the magnetic susceptibility of submilligram amounts of sample. The magnetic field is supplied by a moving permanent magnet, and the susceptibility is determined by the deflection of the spring observed in a measuring microscope. The apparatus is calibrated by a comparison standard (platinum) and results are shown for platinum, nickel aluminate, lead, manganese, and sucrose. A precision of better than 2% can be obtained on submilligram amounts of paramagnetic substances having a magnetic susceptibility of from 1 to 50×10 −6 emu/g. On weakly paramagnetic or diamagnetic substances comparable precision can be obtained on less than 10 mg amounts of sample.

Review of Scientific Instruments↗