Roughening Transition in theHe4Solid-Superfluid Interface

Abstract

17 Previous studies of this model were either restricted to ^ = 0.5 (#=0), N = 2048 sites (Ref. 3) or to concentration c B = 0.25, iV = 500 sites lL. D. Fosdick, Phys.Rev. 1_16, 565 (1959)3 . This lattice size clearly is too small to study the phase transitions, however.18 This estimate is in good agreement with Ref. 3, indicating that the inaccuracy due to finite lattice size is small. 19A significant change of interaction parameters with lattice spacing has recently been revealed even for Principal planes of the 4 He solid-superfluid interface are expected to undergo roughening transitions at temperatures of about 1 K. An experiment is described in which two such transitions were observed in the hep-superfluid interface: first for the basal plane at 1.08 K and second for an orthogonal face at 0.85 K.

Morphological transition of interfacial Ni3Sn4 grains at the Sn-3.5Ag/Ni joint

“…At temperatures close to 0 K, all crystals in equilibrium with a surrounding vapor or liquid are predicted [13][14][15][16][17][18] and have indeed been observed [19][20][21] to be polyhedral with atomically flat, singular surface planes. At high temperatures, each singular surface plane can undergo roughening transition, as predicted initially by Burton et al 22 At the roughening temperature, T R , the planar surface is predicted to become curved, 23 and at high temperatures, some grains even become spherical.…”

The dependence of normal and abnormal grain growth in silver on annealing temperature and atmosphere

“…[15,16] Rottman [17] showed the surrounding fluid are predicted [1,2,3] and have been possibility of the roughening transition of low-angle grain observed [4][5][6][7] to have atomically flat (or smooth or singular) boundaries, and Shvindlerman and Straumal [18] collected surfaces of low index planes and hence polyhedral shapes.…”

Thermal dynamics at surfaces

“…2. Optical holographic interferograms revealed for that system T r (1120) = 0.85 K, whereas T r (0001) = 1.08 K [1]. As a consequence the (1120) face entirely disappeared at already 0.9 K, while the basal plane remained until close to its roughening temperature.…”

“…Figure 2 shows hexagonal close-packed (hcp) 4 He crystals in equilibrium with their superfluid. They display facets at T = 0.4 K, as evident from clearly visible corners and edges [1]. These get rounded when the surface starts to roughen at 1.1 K until the crystal gets spherical at 1.4 K, minimizing the surface to volume ratio under the condition of isotropic surface free energies.…”