The influence of sample geometry on measured physical properties (the magneto-Seebeck effect, Nernst
effect, magnetoresistance effect, Hall effect, and thermal conductivity) in a magnetic field was investigated for
a polycrystalline Bi-Sb sample. The polycrystalline Bi
88Sb
12 bulk sample was prepared using the spark plasma
sintering method and annealing, and the physical properties obtained via measurements in magnetic fields of
5 T were compared with the simulated values obtained by the finite element method with considering various
sample geometries. The appropriate shape required for the precise measurement of less than 2% error was found
to be different for each physical property: the required aspect ratio of length l to width
w is
l/
w > 0.57 for the magnetoresistance effect,
l/
w > 2.9 for the Hall effect,
l/
w > 4.2 for the two-wire magneto-Seebeck effect,
l/
w > 1.2
for the four-wire magneto-Seebeck effect, and
l/
w > 3.1 for the Nernst effect. We also found that a small error of
less than 2% in the thermal conductivity measurement requires
Ks/
Kw > 27, where
Ks and
Kw represent the thermal
conductance of sample and that of lead wire, respectively.
抄録全体を表示