Magnetotransport Effects and Electronic Phase Separation in Manganese Sulfides with Electron-Hole Doping

Romanova, O. B.; Aplesnin, S. S.; Sitnikov, M. N.; Udod, L. V. Journal Of Experimental And Theoretical Physics.

We analyze the effect of electron and hole doping with a low substituent concentration (x = 0.01) on the magnetic and electron subsystems in disordered semiconductors MexMn1 – xS (Me = Ag and Tm) in a wide range of temperatures (77–1000 K) and magnetic fields up to 12 kOe. Using magnetic measurements, we have established the domains of ferron (polaron) formation in the vicinity of the magnetic phase transition. We have detected the magnetoimpedance and magnetoresistance, the magnitude and sign of which depend on the electric field, temperature, and the type of the substituent element. We have determined the temperatures of thermopower peaks associated with deformation of the crystalline structure. We have established the phonon and magnon contributions to charge carrier relaxation using the method of impedance spectroscopy and the Jahn–Teller mode of oscillations from the IR spectra for the system containing silver. We have determined the diffusion contribution to the conductivity from the impedance hodograph in TmxMn1 – xS semiconductors. The experimental results are described using the models of supermagnetic clusters, ferroelectric domains, and the Debye model.