Magnetotransport properties of InMnSb magnetic semiconductor thin films

Abstract

We report on the magnetotransport properties of epitaxial thin films of In 1−x Mn x Sb dilute magnetic semiconductor grown by metal-organic vapor-phase epitaxy. At temperatures below 10 K, a negative magnetoresistance dominates the magnetotransport that is attributed to spin-dependent scattering by localized magnetic moments. Above 10 K, the magnetoresistance is positive and is well described by a two-band model consisting of spin-split hybridized p-d subbands with different conductivities. Hall effect measurements show an anomalous behavior that persists up to room temperature, providing an indication of ferromagnetic order. In addition, magnetization measurements reveal distinct hysteresis loops at room temperature which confirms the ferromagnetism of the films.

Tuning magnetoresistance and exchange coupling in ZnO by doping transition metals

“…3 can be explained by the model proposed by Khosla and Fischer, where the third-order expansion of the s-d exchange Hamiltonian was considered. 24 Correspondingly, a semiempirical expression of the negative MR is given as 14,18,24,25 …”

“…In this model, due to the sp-d exchange interactions the conduction band in ZnO splits into two subbands for spin-up and spin-down carriers with different mobilities. 18 The distribution of carriers in the two subbands is dictated by the temperature, the magnetic field dependent spin-splitting effect, and the thermal activation energy. Such a semiempirical two band model predicts a positive MR, 18…”

Effect of Fe doping on magnetoresistance and exchange coupling of Fe-doped ITO films

“…The parameters a and b depend on several properties as the average magnetization hMi, the spin of the localized magnetic moments S, the exchange interaction integral J, the density of states at the Fermi [26]. In this two-band model, the conduction band in In 2 O 3 splits into two subbands for spin-up and spin-down carriers with different mobilities.…”

Oxygen Vacancy-Induced Room Temperature Ferromagnetism and Magnetoresistance in Fe-Doped In2O3 Films

“…Moreover, the coexistence of spinrelated positive and negative MR usually occurs at the localization boundary at low temperature with semiconductor behavior, 27 also implying intrinsic ferromagnetism in our (In 1−x Fe x ) 2 O 3 films. A semiempirical expression proposed by Khosla and Fischer, including the negative and positive MR contributions was used to fit the experimental MR curves: 30,31 …”