Transport Properties of Ge1-xMnxSe System

Study of the ac and dc conductivities of semimagnetic semiconductor
Ge1-xMnxSe (x = 0.1 and 0.2) has been carried out. The activation energy and
the pre-exponential factor which appear in the dc conductivity are found to
decrease with increasing Mn. The dielectric response and ac conductivity of the
samples are investigated in the frequency range from 50 Hz to 5 MHz and
temperature range from 300 to 420 K. The obtained data reveal that sac(w)
obey the relation sac(w) = A ws, and the exponent s was found to be » 1. The
analysis of results shows that the dominant conduction mechanism follows the
quantum mechanical tunneling (QMT). The ESR spectra showed that the
investigated samples are paramagnetic materials at room temperature. The
calculated number of defects illustrates that with increasing Mn the number of
defects increases. The magnetic properties are determined by the measurement
of magnetization as a function of magnetic field. The results indicated the
paramagnetic behavior for x = 0.1. While as x increased to 0.2 the results
indicated the ferromagnetic exchange interaction between the magnetic ions.
Keywords: Transport Properties, Magnetic Properties and Semimagnetic
Semiconductors.