The de Haas-van Alphen Effect in Antimony

The de Haas-van Alphen Effect in antimony single crystals was studied by means of a torque method at liquid helium temperature in magnetic fields up to 23 kilogauss, which were applied parallel to the trigonal-bisectrix, the trigonal-binary and the binary-bisectrix planes. New carrier oscillation periods were observed in addition to the periods corresponding to the tilted ellipsoidal Fermi surfaces proposed by Shoenberg, and the corresponding mass parameters were evaluated. These new carrier oscillation periods agree with two possible models of the Fermi surface for the hole. They are discussed with reference to the number of carriers

The de Haas-van Alphen Effect of Zinc

The de Haas-van Alphen effect of pure zinc crystal was investigated at temperatures ranging from 63°to 1.3°K by means of a torsion magnetometer. In the magnetic field less than 16 kilo-oersted and at the temperatures 4.2°K and above, a remarkable periodic variation of magnetic susceptibility was found with the intensity of magnetic field and it is here referred to as the long-period effect. While in the field higher than 19 kilo-oersted and at temperatures from 4.2°to 1.3°K, it was observed that a shorter-period and smaller-amplitude effect, which is accompanied by some complicated beat structures, is superposed on the high field extension of the long-period effect just cited. From the analysis of the long-period effect, we obtained the next de Haas-van Alphen parameters : E_=5.5×10^ erg, m_/m_0=5.4×10^, m_/m_0=2.7×10^, T_=400°K, n_l=1.2×10^atom^; and from the analysis of the short-period effect, we got : E_=7.9×10^ erg, m_/m_0=1.6×10^, m_/m_0=8.3×10^, T_=570°K, n_s=3×10^ atom^

The de Hass-van Alphen Effect in InBi

The de Haas-van Alphen effect in InBi single crystals has been studied by means of a torque method at liquid helium temperatures in magnetic fields up to 23 kilogauss. Three different oscillation periods were observed in the fields which were applied parallel to the plane including the c-axis. Each maximum period in oscillations was attained at the magnetic field parallel to the c-axis, and the periods decreased as the field was rotated. The effective masses and the collision broadening parameters were obtained from the field and temperature dependence of the amplitude of the de Haas-van Alphen oscillations. On the other hand, the de Haas-van Alphen oscillations were not observed with the fields in the case when the c-axis was set vertically. The shapes and sizes of the Fermi surfaces deduced from the three periods of oscillations above mentioned are described

On the Electronic Structure of Bismuth and Its Dilute Alloys

We studied the quantum oscillatory phenomena which were observed at 1.2～4.2°K in the de Haas-van Alphen effect, the magneto-acoustic attenuation, and the Shubnikov-de Haas effect of pure bismuth and its alloys doped with a small amount of tin, tellurium, antimony, arsenic or manganese. Our results obtained in this study with respect to pure bismuth, are in good agreement with the results of the other investigators. From the change of the periods of Shubnikov-de Haas oscillations in dilute bismuth alloys, we discussed the electronic band structure in the higher and lower energy parts than the Fermi level of pure bismuth, and could conclude that the Cohen\u27s model gives a better approximation for the comprehension of the results

Two effects of iodine intercalation on T_c in Bi_2Sr_2Ca_<1-x>Y_xCu_2O_8 : Two-dimensionality and charge transfer

Effects of stage-1 iodine-intercalation on T_c have been investigated in Bi_2Sr_2Ca_Y_xCu_2O_8. The iodine intercalation causes two large effects; one is a change of the two-dimensionality due to an expansion of the crystal along the c-axis, the other is an increase of conducting hole carriers due to charge transfer between intercalated iodine atoms and CuO_2 sheets in the host material. For the stage-1 iodine-intercalation compounds, it has been found that the former effect decreases T_c by about 10 K and that the latter effect shifts the x dependence of T_c to larger x values by about 0.05 because of the increase of conducting hole carriers by about 0.025 per CuO_2 unit. It has been concluded that the decrease in T_c through iodine intercalation in Bi_2Sr_2CaCu_2O_8 is due to the both effects

Upper Critical Field and Resistive Tail in High-T_c Cuprates(High-T_c Superconducting Materials Research)

The electrical resistivity under magnetic fields has been investigated for Pb_2Sr_2Y_Ca_xCu_3O_8, single-crystal Bi_2Sr_2CaCu_2O_8 and low-T_c (La, Eu)_(Ba, Sr)_XCuO_4. The upper critical field and the resistive tail in the lower portion of the superconducting transition curve are discussed