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We have grown single crystal whiskers of Bi 2 (SrCa) n +1 (Cu 1− x Co x ) n O 8− δ with 0 x R as a function of the temperature T . For x n =2 in the majority of the sample and n =3 in a small part. For both phases, the changes in T c and in the extrapolated residual resistance due to Co substitution are the same for Co as it is for Zn and Ni, indicating that magnetic scattering is not important. For x ≈0.06, oxygenation can drive the sample from superconducting to insulating, indicating that both the scattering of the carriers and the number of carriers affect the superconducting–insulating transition. This occurs in samples in which the sheet resistance in a CuO plane is approximately h /(2 e ) 2 . For x >0.18, the samples are insulating and n =1.

We have measured the change in the resistive ${T}_{c}$ of ${\mathrm{Bi}}_{2}(\mathrm{SrCa}{)}_{2+n}({\mathrm{Cu}}_{1\ensuremath{-}x}{M}_{x}{)}_{1+n}{\mathrm{O}}_{y}$ whiskers due to substitution of $M$ = Ni (magnetic) or $M$ = Zn (nonmagnetic) for Cu. These whisker crystals show resistance drops for both the 2212 and 2223 $(n=1,2)$ phases, with transition widths (10--90 %) of 1 K. We checked the effect of oxygenation at several values of $x$, and found that ${T}_{c}$ is maximum for the $y$ obtained by growing and annealing in 1 atm of ${\mathrm{O}}_{2}$. We observed a linear depression of ${T}_{c}$ for both 2212 and 2223 phases with ${D=dT}_{c}/dx\ensuremath{\approx}\ensuremath{-}800$ K for both Ni and Zn. This is in contrast with YBCO in which ${D}_{\mathrm{Zn}}\ensuremath{\approx}{3D}_{\mathrm{Ni}}.$

We have measured the resistivity of (Bi,Pb${)}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{Ca}}_{\mathit{n}\mathrm{\ensuremath{-}}1}$${\mathrm{Cu}}_{\mathit{n}}$${\mathrm{O}}_{\mathit{x}}$ single-crystal whiskers in the a and c directions. Our results indicate that the whiskers may be either 2:2:1:2 (n=1) or 2:2:2:3 (n=2) or have both phases present. Well above ${\mathit{T}}_{\mathit{c}}$, the resistivity in the a direction decreases linearly with temperature. We also studied the paraconductivity due to thermal fluctuations above ${\mathit{T}}_{\mathit{c}}$. The paraconductivity in the a direction shows quasi-one-dimensional behavior for temperatures close to ${\mathit{T}}_{\mathit{c}}$. This quasi-one-dimensional behavior may be due to a percolative conduction path. For the c direction, the resistivity is best fit by ${\mathrm{\ensuremath{\rho}}}_{\mathit{c}}$=${\mathit{Ae}}_{\mathit{g}}^{\mathrm{\ensuremath{-}}\mathit{E}}$/kT, where T is the temperature. However, as T approaches ${\mathit{T}}_{\mathit{c}}$ from above, ${\mathrm{\ensuremath{\rho}}}_{\mathit{c}}$ increases much faster than a thermally activated law, perhaps because of the fluctuations.

We have measured the resistive superconducting transition temperature of single-crystal whiskers of Bi{sub 2}(SrCa){sub n+2}(Cu{sub 1-x}M{sub x}){sub n+1}O{sub y} in which M represents the transition metals Fe and Pd that have been partially substituted for Cu. Combining these measurements with our earlier results for Co, Ni, and Zn substitutes, we derive a general relationship for the rate at which T{sub C} is depressed by substitution of transition metals: dT{sub C}/dx{approx}-780K for all these elements and both the 2212 (n=1) and 2223 (n=2) phases. Further, the normalized residual resistance is also a universal function of x. This is contrary to what others find for YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} (YBCO), in which Zn and Ni substitutions act quite differently on dT{sub C}/dx. The explanation of this effect in YBCO apparently does not involve the general behavior of the Cu-O planes. The magnitude of dT{sub C}/dx is about half that predicted by the Abrikosov-Gorkov relation, as seen in other Cu-O superconductors.

We have measured the effect of elastic stress σ on the resistivity ρ of BiSCCO whiskers in the a - and c -directions, with the stress along the a -axis. We find, in units of GPa −1 , dln(ρ a )/dσ 11 =(0.064±0.020) and dln(ρ c )/dlnσ 11 =(0.28±0.05). Combining these results with those of Forro et al . [dln(ρ a )/dP=−0.075 GPa − and dln)ρ c ) dP=−0.4 ∗ ] and assuming (a) BiSCCO to be tetragonal and (b) dρ 33 dσ 11 = dρ 11 dσ 33 , we estimate the tensor dρ i dσ j =[A ij ] . Estimating the elastic constants, we laso find Bij=dρ i d j .

We have made ultrasonic and Brillouin scattering measurements at ambient temperature on small single crystals of monoclinic ZrO2. Using these data, we have established various features of the angular anisotropy in the acoustic longitudinal wave and shear wave velocities, and we have computed the elastic stiffness and compliance moduli. We observe shallow minima in the transverse shear wave velocity in directions parallel to the a and c crystallographic axes. We anticipate that acoustic shear wave softening will be observed in these directions when measurements are made at temperatures close to the monoclinic-tetragonal transformation.

The temperature dependence of the $^{197}\mathrm{Au}$, $^{166}\mathrm{Er}$, and $^{169}\mathrm{Tm}$ M\"ossbauer effect has been studied in intermediate phases of $R\mathrm{Au} (R=\mathrm{S}\mathrm{c},\phantom{\rule{0ex}{0ex}}\mathrm{H}\mathrm{o},\phantom{\rule{0ex}{0ex}}\mathrm{E}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{T}\mathrm{m},\phantom{\rule{0ex}{0ex}}\mathrm{Y}\mathrm{b},\phantom{\rule{0ex}{0ex}}\mathrm{L}\mathrm{u})$ with the CsCl structure. Our results indicate that the CsCl structure is metastable and undergoes a low-temperature martensitic phase transformation to a close-packed (FeB-like) structure. The ratio of the quantity of the two phases present at 4.2\ifmmode^\circ\else\textdegree\fi{}K for various compounds is obtained. M\"ossbauer-absorption patterns for $^{166}\mathrm{Er}$ in ErAu have a temperature dependence which is characteristic of relaxation effects. Isomer-shift systematics for $^{197}\mathrm{Au}$ in $R\mathrm{Au}$ for the CsCl and the transformed close-packed phases are discussed.

Hardness, density, and thermal expansion data are presented for alloys of uranium with certain fissionproduct elements. The elements are those expected to remain in a spent fuel from a fasi reactor following pyrometallurgical refining. In cast and gamma quenched alloys the reteniion of the high- temperature gamma phase produces low hardness and low density. Thermal expansion behavior is dependent upon composition and prior thermal history. (auth)

All binary and a number of ternary σ alloys formed by first long period transition elements were examined and found to be ferromagnetic at low temperatures. The Curie temperatures for these alloys were measured. It was found that the correlation of the Curie temperature with composition may be described qualitatively in terms of the contributions of the various component atomic moments to the saturation moment of the alloy. Ternary Fe-Cr-Mo σ phase alloys were also found to be ferromagnetic, with a Curie temperature dependent on the iron content and largely independent of the unit cell dimensions. Similar relations were found for the Co-Fe-Cr and the Co-Cr-Mo σ alloys, where the Co + Fe content appears to determine the Curie temperature.

Saturation magnetizations of V‐Fe and Cr‐Fe alloys were measured and the results used to determine the average atomic magnetic moment. The linear rate of change of the moment with solute concentration, dpB/dC, was found to be −3.286 Bohr magnetons per atom in V‐Fe α‐phase alloys. Transformation of an approximately equiatomic alloy to the CsCl‐ordered α′‐phase resulted in a decrease of about 0.4 Bohr magneton in the moment. Subsequent transformation to the σ‐phase lowered it by a factor of three. In Cr‐Fe solid solution alloys, dpB/dC was found to be −2.36 Bohr magnetons per atom.

The M\"ossbauer technique has been used to investigate the magnetic hyperfine field and electric quadrupolar coupling at Fe nuclei in $\ensuremath{\chi}$-phase ternary alloys and in antiferromagnetic MnFe alloys having the $\ensuremath{\alpha}$-Mn structure. Alloys with 5, 10, 20, and 30 at.% Fe in $\ensuremath{\alpha}$-Mn and the $\ensuremath{\chi}$-phase alloys $\ensuremath{\chi}({\mathrm{V}}_{30}{\mathrm{Si}}_{20}{\mathrm{Fe}}_{50})$, $\ensuremath{\chi}({\mathrm{Ti}}_{17}{\mathrm{Cr}}_{24}{\mathrm{Fe}}_{59})$, and $\ensuremath{\chi}({\mathrm{Mo}}_{17}{\mathrm{Cr}}_{21}{\mathrm{Fe}}_{62})$ were examined at 4, 77, and 300\ifmmode^\circ\else\textdegree\fi{}K. The data are consistent with the assumption that of the four available sets of sites, Fe occupies only sites III and IV. The Fe atoms appear to have no aligned $3d$ moment. For FeMn alloys the fact that the spectra at a given temperature are nearly independent of composition indicates that (1) the ratio between the Fe populations of the two sites is the same for each composition, and (2) the isomer shift, the magnetic field, and the electric-field gradient at an Fe site are not sensitive to whether neighboring atoms are Fe or Mn. A different Debye temperature is associated with Fe at each site.

Magnetic susceptibilities and nuclear magnetic resonance measurements have been made on V-Fe alloys up to 34 at.% Fe in V. The composition and temperature dependence of the susceptibilities and of the NMR linewidth of ${\mathrm{V}}^{51}$ suggests the appearance of magnetic moments at about 23 at.% Fe. The Knight shifts of ${\mathrm{V}}^{51}$ in the nonmagnetic portion of this alloy system are discussed in terms of the contributions from the Fermi contact term, $\mathrm{sd}$ exchange, and induced orbital paramagnetism.

Our heat-capacity measurements on a well-characterized sample of YBa/sub 2/Cu/sub 3/O/sub 6.85/ yield ..delta..C/sub p//T/sub c/approx. =20 mJ (mole Cu)/sup -1/ K/sup -2/, essentially the same value found previously for La/sub 1.85/Sr/sub 0.15/CuO/sub 4/. We combine this finding with independently estimated values of ..gamma.., the electronic specific-heat coefficient, to show that ..beta.. = ..delta..C/sub p//..gamma..T/sub c/ is (1) well outside the weak-coupling regime (..beta../sub BCS/ = 1.43) for the Y-based compound (T/sub c/ = 93 K) and La-based compound (T/sub c/ = 31 K), and (2) larger by about a factor of 2 in the Y-based compound compared to the La-based compound, the latter having a ..beta.. value in the same numerical range (2--3) as previously studied strong-coupling superconductors.

The heat capacity has been obtained for a sample of ${\mathrm{La}}_{1.85}$${\mathrm{Sr}}_{0.15}$${\mathrm{CuO}}_{4}$ which is superconducting with a transition temperature ${T}_{c}$=31 K. Although the heat capacity is dominated by the lattice in the vicinity of ${T}_{c}$, it has nonetheless been possible to observe the superconducting transition, thus verifying that this is bulk superconductivity. A lower limit is established for the heat-capacity anomaly of \ensuremath{\Delta}C/${T}_{c}$=(20\ifmmode\pm\else\textpm\fi{}5) mJ/mole ${K}^{2}$. Combined with estimates of the electronic heat capacity \ensuremath{\gamma}, this leads to 2\ensuremath{\le}\ensuremath{\Delta}C/\ensuremath{\gamma}${T}_{c}$\ensuremath{\le}10, compared with the Bardeen-Cooper-Schrieffer value of 1.43, which places this material well into the strong-coupling regime.

Magnetization curves were determined for the CsCl‐type compound TiFe at six temperatures ranging from 9°K to 110°K. The curves show a saturation effect at high field strength but they are of a form that is not characteristic of ferromagnetism. A saturation magnetization of 3.30±0.07 cgs units per gram was derived from the high field data. This moment is tentatively interpreted as resulting from a small concentration of uncompensated spins produced by disorder in the CsCl‐type lattice. The electrical resistance of samples of TiFe was measured over the temperature range from 10°K to room temperature. Magnetization measurements were attempted on the CsCl‐type compounds TiCo and TiNi, but their magnetizations were too small to be detected.

The heat capacity has been obtained for superconducting samples of La1.85Sr.15CuO4 1 and REBa2Cu307-x 2,3 (RE = Gd,Dy,Ho,Er). The ∆C/yT values of 2 to 5 for the La1.85Sr0.15CuO4 compound places this material well into the strong coupling limit From the data for REBa2Cu3O7-x, the degeneracies of the crystal field ground state are determined and the magnetic moment in the ground state and the energy separation to the first excited crystal field state are estimated. The magnetic transitions are observed at Tm = 2.2, 0.95, 0.17, and 0.59 K for the Gd, Dy, Ho, and Er compounds, respectively. The antiferromagnetic ordering of the Gd ions is independent of the presence or the absence of superconductivity and is unchanged in both insulating and metallic systems.

A number of the properties covered in this chapter are also given elsewhere in this volume. In this presentation, the properties of the actinide elements arc taken as a whole and attempts are made to compare them with the properties of metallic elements occurring in other parts of the periodic table. The actinide metals arc often thought to be exotic, because they tend to have properties that are difficult to explain by simple theoretical approaches that have been useful for simple metals. The properties of the actinide metals do in fact represent a severe test to the theoretical solid-state scientist, as do the other transition-metal series. But, like other metals, they are lustrous and may be malleable; they have, among their several crystalline structures, some simple atomic arrangements; and they have relatively low electrical resistivities and high thermal conductivities.

A review of the structure types in binary alloy sigma , mu , an X phases of transition elements is presented. Information is included on ternary alloys in which the P and R intermediate phases appear also. lt is noted that proceeding from the A-component end, the phases occurring at fixed stoichiometric ratios have structures such as at AaB the Cr/sub 3/O-type; at A/sub 2/B the Ti/ sub 2/Ni-type (eta-carbide), the MoSi/sub 2 type (C11B), and the CuAl/sub 2/-type (C16); at the equiatomic composition the CsCl-type (B2); at AB/sub 2/ the MgCu/ sub 2/-type C15), the MgZn/sub 2/-type (C14), the MgNi-type (C36), and another group of MoSi/sub 2/-type phases; at AB/sub 3/ a group of close-packed ordered CN12 structures; and at the AB/sub 5/ composition the UNi/sub 5/-type (C15/sub beta /) and the CaCu/sub 5/-type (D2/sub delta /). The emphasis in the review is on structure relations, occurrence regularities, and the effects of atomic sizes and electronic factors. (J.R.D.)

Mossbauer spectroscopy has been used to investigate intermetallic compounds of the Fe–Mn system with the β‐Mn structure. The data are analyzed using a model based on recent NMR results of Drain. Although β‐Mn is nonmagnetic, alloy phases containing 10 at. % or more of Fe are magnetically ordered at 4.2°K. Iron is found to preferentially occupy Site II. The slight dependence of the isomer shift and quadrupolar coupling on Fe concentration is indicative of the electronic similarity of Fe and Mn in a given site. The average Debye temperature for Fe in β‐Mn is ∼100° larger than that for Fe in α‐Mn.