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The purpose of this study was to investigate the magnetotransport properties of the Ge(0.743)Pb(0.183)Mn(0.074)Te mixed crystal. The results of magnetization measurements indicated that the compound is a spin-glass-like diluted magnetic semiconductor with critical temperature TSG = 97.5 K. Nanoclusters in the sample are observed. Both, matrix and clusters are magnetically active. Resistivity as a function of temperature has a minimum at 30 K. Below the minimum a variable-range hopping is observed, while above the minimum a metallic-like behavior occurs. The crystal has high hole concentration, p = 6.6E20 cm-3, temperature-independent. Magnetoresistance amplitude changes from -0.78 to 1.18% with increase of temperature. In the magnetotransport measurements we observed the anomalous Hall effect (AHE) with hysteresis loops. Calculated AHE coefficient, RS = 2.0E6 m3/C, is temperature independent. The analysis indicates the extrinsic skew scattering mechanism to be the main physical mechanism responsible for AHE in Ge(0.743)Pb(0.183)Mn(0.074)Te alloy., Comment: 4 pages, 3 figures

We consider theoretically the topological contribution to the anomalous Hall effect in narrow-gap IV–VI magnetic semiconductors in which the relativistic terms are relatively large and determine both the non-parabolicity of the energy spectrum and strong spin–orbit interaction. We use the relativistic Dirac model and linear response theory to calculate this contribution. Experimental data on the anomalous Hall effect in these compounds are also presented and discussed.

Interesting possibilities of application gives co‐occurrence of ferroelectric and ferromagnetic properties. GeMnTe is known to possess such unique properties. Here, we report preliminary AC magnetic susceptibility and magnetization studies of GeMnTe co‐doped with another magnetic ion — Europium, aimed at investigating of Eu ions influence on the magnetic properties of the resulting quaternary compound. We found that the Curie temperature of GeMnEuTe substantially (about 3 times) exceeds the values of TC reported in GeMnTe crystals and layers with similar Mn composition, equal ∼40 K. The origin of this substantial Curie temperature enlargement is not fully explained yet. However, the spin‐echo resonance data may suggest that the Mn2+ ions system is in a mixed valence state and that an additional channel of interaction between magnetic ions is open.

Magnetic and transport properties of ferromagnetic semiconductors (FMSs) near the ferromagnetic-paramagnetic phase transition were studied in two classes of FMSs: in the III–V-based In1−xMnxSb and Ga1−xMnxAs epitaxial films and in IV–VI-based Sn1−xMnxTe and Sn1−x−yMnxEryTe alloys in bulk crystal form. Magnetoresistance data for both FMS classes are in excellent agreement with the theory of Majumdar and Littlewood, indicating that near the Curie temperature, magnetic fluctuations play a key role as scattering centers. These results also show that the Majumdar–Littlewood model can be applied to magnetically very dilute systems.