High resolution miniature dilatometer based on an atomic force microscope piezocantilever.

Thermal expansion, or dilation, is closely related to the specific heat, and provides useful information regarding material properties. The accurate measurement of dilation in confined spaces coupled with other limiting experimental environments such as low temperatures and rapidly changing high magnetic fields requires a new sensitive millimeter size dilatometer that has little or no temperature and field dependence. We have designed an ultracompact dilatometer using an atomic force microscope piezoresistive cantilever as the sensing element and demonstrated its versatility by studying the charge density waves in alpha uranium to high magnetic fields (up to 31 T).

Thermal expansion and magnetostriction of pure and doped RAgSb(2) (R = Y, Sm, La) single crystals.

Data on temperature-dependent, anisotropic thermal expansion in pure and doped RAgSb(2) (R = Y, Sm, La) single crystals are presented. Using the Ehrenfest relation and heat capacity measurements, uniaxial pressure derivatives for long range magnetic ordering and charge density wave transition temperatures are evaluated and compared with the results of the direct measurements under hydrostatic pressure. In-plane and c-axis pressure have opposite effects on the phase transitions in these materials, with in-plane effects being significantly weaker.

Thermal expansion and effect of pressure on superconductivity in Cu(x)TiSe(2).

We report measurements of thermal expansion on a number of polycrystalline Cu(x)TiSe(2) samples corresponding to the parts of x-T phase diagram with different ground states, as well as the pressure dependence of the superconducting transition temperature, T(c), for samples with three different values of Cu doping. Thermal expansion data suggest that the x-T phase diagram may be more complex than initially reported. T(c) data at elevated pressure can be scaled to the ambient pressure Cu(x)TiSe(2) phase diagram; however, significantly different scaling factors are needed to accommodate the literature data on the charge density wave transition suppression under pressure.

Magnetic-field-induced lattice anomaly inside the superconducting state of CeCoIn5: anisotropic evidence of the possible Fulde-Ferrell-Larkin-Ovchinnikov state.

We report high magnetic field linear magnetostriction experiments on CeCoIn5 single crystals. Two features are remarkable: (i) a sharp discontinuity in all the crystallographic axes associated with the upper superconducting critical field B(c2) that becomes less pronounced as the temperature increases and (ii) a distinctive second orderlike feature observed only along the c axis in the high field (10 T < or approximately B< or = B(c2)) low temperature (T < or approximately 0.35 K) region.

Tricritical phenomena at the gamma-->alpha transition in Ce0.9-xLaxTh0.1 alloys.

The gamma-->alpha isostructural transition in the Ce0.9-xLaxTh0.1 system is measured as a function of La alloying using specific heat, magnetic susceptibility, resistivity, thermal expansivity or striction measurements.