Shubnikov de Haas oscillations

The Shubnikov-de Haas oscillations were observed by ac (337Hz) method with current (I=100pA) directed parallel to the c -axis. The de Haas-van Alphen oscillations were studied with cantilever torquemeter [4], The magnetic fields used were up to 14 T for both types of experiment and the temperature range was 1.5-4.2K. 

Figure 6. FFT spectrum for Shubnikov-de Haas oscillations (inset) for (BEDO-TTF)5[ScHg(SCN)4]2 at T=1.55K and the field direction parallel to the c -axes (0=0°). Four different frequencies Fi 650T, F2 2600T F3 3200T and F4 3850T are clearly seen.

Fig. 21. Transverse magnetoresistance of (BEDT-TTF)2[KHg(SCN)4]. An unusual resistance decrease can be seen above 10 T, with a kink structure at 22 T indicated by the large arrow. The small arrows indicate Shubnikov-de Haas oscillations [34].

Fig.2. Fourier spectrum of magnetoresistance (Shubnikov-de Haas) oscillations for fields normal to the crystal bc-plane...

The electronic structure of ET2Cu(NCS) was established to be of two-dimensional nature by the observation of Shubnikov-de Haas oscillations as a function of angle at 0.3 K and in magnetic fields between 14 T and 22 T. The SdH frequency,for magnetic fields perpendicular to the cation layers, was found consistently to be 597 7 T for samples from six different batches. This result agrees qualitatively with the published band structure, but is about 10% smaller than the value derived from a previous study in magnetic fields below 13.5 T. 

Shubnikov-de Haas oscillations were detected in CeAs (Kwon et al. 1991, Takeda et al. 1993). For a good stoichiometric sample of CeAs, the carrier number is one order of magnitude smaller than that of CeSb. Branches a, and )8 were observed, although branch due to a hole Fermi surface in band 3 was not observed. The topology of the Fermi surface is similar to that of LaSb, although the volume is small compared to LaSb, as shown in fig. 56. 

Magnetoresistance measurements were done for SmCu2, indicating that it is a compensated metal with open orbits, at least, along the b-axis (Maezawa et al. 1986). Shubnikov-de Haas oscillations were observed in the magnetoresistance. The detected dHvA frequencies are in the range of (0.68-1.25) x 10 Oe. 

Note Tc is defined by the midpoint of resistance jump (until otherwise noted) except for the C q family, where is usually defined by the onset of diamagnetization. SDW spin density wave D-O disorder-order transition of anion FISDW field-induced SDW SdH Shubnikov-de Haas oscillation fee face-centered cubic, se simple cubic, bet body-centered tetragonal /cf face-centered tetragonal rf radio frequency. 

The Hall effect of boron carbide is small (Fig. 35a and b). It depends on composition and temperature (14,147-149). Because the calculation of the Hall mobility from the measured Hall constant depends strongly on the electronic transport mechanism, which for boron carbide has not yet been finally solved, the mobilities calculated after classical theories and shown in Fig. 35 are somewhat questionable. Hall effect and magnetoresistance were measured up to 15 T (Figs. 36 and 37) (157). The behavior expected from classical theory was confirmed in a large range, and for B > 13 T the magnetoresistance seems to indicate beginning Shubnikov-de Haas oscillations. The transport parameters obtained are listed in Table 3. 

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