Zn Single Crystal Research Articles

Anisotropy in the Kondo effect of single crystal Zn–Mn alloys

The anisotropy in the Kondo effect of single crystal ZnMn alloys (10–500 at. ppm Mn) has been studied between 0.3 and 8 K. The impurity resistivity with current flowing perpendicular to the c-axis of the hexagonal crystal is 1.6 times greater than the impurity resistivity with the current flowing parallel to the c-axis for all the ZnMn alloys. The resistivity of a Zn 500 at. ppm Al alloy was found to be isotropic and, in agreement with previous results, the resistivity of pure zinc was found to be nearly isotropic. On the basis of a two band model for zinc we show that the ratio the relaxation time on the monster and lens portions of the Fermi surface τL/τM is 1.3 ± 0.1 for pure Zn, 1.1 ± 0.3 for the ZnAl alloy, and 0.43 ± 0.05 for the ZnMn alloys. We attribute the threefold variation of τM/τL between magnetic Mn (d-type) impurities and the nonmagnetic (s,p-type) impurities in pure Zn and the ZnAl alloys to the nature of the conduction electron wave functions on the monster and lens portions of the Fermi surface of Zn. We require the partial density of s,p-like wave functions to 1.2 times greater on the lens surface than on the monster surface while the partial density of d-like wave functions on the lens surface must be 0.4 times their density on the monster surface.

The sign of the electric field gradient at the nuclear site of Zn in Zn metal

By use of low temperature nuclear quadrupole orientation the quadrupole coupling constant of69mZn in a Zn single crystal has been determined asvQ=eQVzz/h=−28(3) MHz.

The sign of the quadrupole interaction of the 828 keV state of115In in Zn

Sign and magnitude of the electric quadrupole interaction of the 828 keV state of115In in a Zn single crystal was determined by aβ-γ TDPAC measurement. The result:v Q =e·'QIV zz /h=−193(13)MHz confirms the universal correlation between the electronic and ionic contributions to the total electric field gradient proposed by R.S. Raghavan et al.

Two-Magnon Linewidth Induced by Multipole Demagnetizations of Surface Imperfections on Zn2Y

On single crystal Zn 2 Y , the experimental linewidth induced by surface imperfections is compared with the theoretical one. The theoretical calculation is made in consideration of dipole and quadrupole demagnetizations of the imperfections and with the use of the effective exchange constants D ⊥ =0.15×10 -9 Oe cm 2 and D // =9.3×10 -9 Oe cm 2 within and between the crystallographic c planes. The experimental linewidth agrees well with this calculation rather than the other two results calculated by Sparks-Loudon-Kittel and Seiden-Sparks methods. The ratio of the quadrupole contribution to the dipole increases with decrease of polishing grit size. The extended calculation for the higher order multipoles than the quadrupole achieves the more precise approach of the calculated linewidth to the experimental one.

Anti-phase domain growth kinetics in β′ phase AgZn

Anti-phase domain growth was studied in a quenched β′ phase Ag-43 atom % Zn single crystal. X-ray line breadth analysis showed that the domain growth rate changes over a five decade range within the temperature interval 23 C to 99 C. The experimentally determined growth kinetics are substantially different from those found in other alloy systems and from those predicted by theory.

Lamellar glass-crystal structures in the system ZnO-B 2O 3

Lamellar glass-crystal structures were grown by progressive solidification of the eutectic in the system ZnO-B 2O 3. Movement of the growth isotherm at a velocity of 10 -4cm/sec yielded an average lamellar spacing of 0.004 cm, whereas a velocity of 10 -5cm/sec produced an average spacing of 0.04 cm. Since the product of lamellar spacing and imposed growth velocity was constant and equal to 4×10 -7 cm 2/sec, the implication was that phase separation during solidification was diffusion limited. The laminate was composed of alternate laths of single crystal Zn 5B 4O 11 and vitreous ZnB 2O 4. Heat treatment of the glass-crystal structure caused the vitreous phase to devitrify into submicron grain size ZnB 2O 4 crystallites. Both the glass-crystal and polycrystalline-crystal structures exhibited higher resistivities (≅10 12 ohm-cm) when the applied field was perpendicular to the lamellae rather than when the field was parallel to them. In the case of the polycrystalline-crystal structure, the resistivity differed by a factor of 40 for the parallel and perpendicular directions over the range from 40 to 4000 V(DC)/cm.

High Power Behavior and Spin-wave Spectrum in a Hexagonal Ferrite with Large Planar Anisotropy

Anisotropy of the absorption saturation of ferromagnetic resonance under a high r f -field was measured in a spherical sample of single crystal Zn 2 Y by the parametric excitation method. The measured absorption consists of three parts: a main mode and two subsidiary absorptions. To analyse the high power behaviors of these absorption peaks, an anisotropic dispersion relation of spin waves is derived from a phenomeno-logical treatment. The first and the second order non-linear behaviors are distinguished clearly in agreement with theory. Details of two subsidiary peaks accompanying with the main mode resonance are explained in terms of the dissipation processes due to the excitation of the spin wave corresponding to the obtained spectrum.

Some Observations on Creep in Zinc Single Crystals

A concentrated load, applied to the surface of a Zn single crystal, produces a hexagonal dimple if this surface is parallel to the basal plane of the crystal lattice. The rim of these dimples is formed by six sets of edge dislocations moving into the six slip directions with increasing loading time, thus causing the dimple to grow. The dimple contours can be photographed with a microfocus x-ray tube. Measurements of a large number of dimples showed: (1) For a given loading time, dimple size increases linearly with the applied load. (2) For a given load, dimple size increases with loading time until the shear stress at the dimple rim has been lowered to a value characteristic for the material used, below which creep velocity is either zero or extremely low. (3) This critical shear stress is independent of temperature. (4) It depends on the impurity concentration of the crystal in the way predicted by the model of Cottrell.

金屬中に於ける價電子の勢力状態に就て(第9報)

The selectivity of photo-electron transition in the surface of zinc crystal was closely examined, and found that it has an intimate relation with the direction of the oscillating electric vector of the exciting light. Further, applying the results obtained from the electrode potentials of the surfaces of Zn-single crystal, it was inferred that the selection rule, Δ=±1, is explicable from the fact that the stability of orbital motion of the election depends on the mutual orientation of the orbital plane and the electric vector of the exciting light. On the basis of this conception it was concluded that the orbital planes of p and d electrons in the energy levels, E2 and E3, in the surface layer of zinc crystal are perpendicular and parallel, respectively to the axis, [0001], of the crystal of this metal.

Thermo-Electric Effect in Single Crystal Zinc

Thermal e.m.f., thermo-electric power, Peltier heat of single crystal Zn against Cu as functions of crystal orientation.---In continuation of previous work data are presented on the thermal e.m.f. against copper of six single crystal wires of zinc, of which the orientations of the main crystallographic (hexagonal) axis with respect to the wire axis, range from 11.4\ifmmode^\circ\else\textdegree\fi{} to 90\ifmmode^\circ\else\textdegree\fi{}. (The average deviation from the mean for these observations is 0.8\ifmmode^\circ\else\textdegree\fi{}.) The temperature interval is from - 182\ifmmode^\circ\else\textdegree\fi{} to 475\ifmmode^\circ\else\textdegree\fi{}C. The apparatus designed to enable measurements to be made above the melting point is described in detail.Thermo-electric power, Peltier heat, and difference of Thomson coefficients for Zn \ensuremath{\perp} against Zn\ensuremath{\parallel}.---From the data are calculated the thermo-electric power, Peltier coefficient, and difference of the Thomson coefficients for Zn \ensuremath{\perp} against Zn\ensuremath{\parallel}. The data also provide a test for the Voigt-Thomson law for the variation of the thermo-electric power with crystal orientation. The law seems to be verified within the limits of experimental error for the low temperatures, but the deviations at the high temperatures (300\ifmmode^\circ\else\textdegree\fi{}-400\ifmmode^\circ\else\textdegree\fi{}) are greater than the experimental errors are thought to be.Thermal e.m.f. of liquid Zn against single crystal and polycrystalline Zn.---Further, the thermo-electric powers of liquid Zn against solid single crystal Zn of different orien tations, and against polycrystalline Zn are given. The value-7.89\ensuremath{\mu}v. per deg. for ${e}_{l}\ensuremath{-}{e}_{s}$ for Zn (polycrystalline) having been found. A theoretical discussion of the thermo-electric effect in polycrystalline substances having different properties along only two of the crystallographic axes, leads to the formula $\overline{e}=(\frac{1}{3})$ ($2e\ensuremath{\perp}+e\ensuremath{\parallel}$), and indicates that such a polycrystalline metal wire should behave the same as a single crystal wire of orientation 54.5\ifmmode^\circ\else\textdegree\fi{}, the experimental value found being between 65\ifmmode^\circ\else\textdegree\fi{} and 70\ifmmode^\circ\else\textdegree\fi{}. It appears from this formula that polycrystalline Zn may be considered as an alloy of two parts Zn \ensuremath{\perp} and one part Zn\ensuremath{\parallel}.