M. Arciszewska

Magnetic phase diagram of Pb1−x−ySnyMnxTe semimagnetic semiconductors

Abstract Magnetic susceptibility and Hall effect in Pb1−x−ySnyMnx semimagnetic semiconductor with 0.03 ⩽ x ⩽ 0.12 were investigated as a function of carrier concentration. At low temperatures a ferromagnetic phase was observed in the samples with a high carrier concentration. The dependence of the Curie temperature Tc on the carrier concentration p has a threshold-like character for all investigated samples. The threshold hole concentration depends on the Mn content and decreases with increasing concentration of manganese ions. The results are summarized in the form of Tc(x,p) magnetic phase diagram.

Spin-glasslike behavior in rhombohedral (Ge,Mn)Te–(Sn,Mn)Te mixed crystal

We present studies of magnetic and transport properties of Ge1−x−ySnxMnyTe mixed crystals with chemical compositions 0.083≤x≤0.142 and 0.012≤y≤0.119. The transport characterization measurements were performed at temperatures 4.2 1021 cm−3. It was found that the transport properties strongly depend on the chemical composition of the alloy. The magnetic investigations included measurements of linear χ1 and harmonic χ2,3 ac susceptibilities as a function of temperature and of the applied magnetic field amplitude and frequency. Qualitative analysis of our experimental data showed that in the studied system, in the investigated composition range, the spin glass order exists at temperatures up to 50 K.

Magnetic and electronic properties of Sn1−xGdxTe

Magnetic susceptibility, electron paramagnetic resonance and transport properties of Sn 1−x Gd x Te semimagnetic semiconductor with 0.04 ≤ x ≤ 0.07 were investigated as a function of carrier concentration. For crystals with x p*

Magnetoresistance near the ferromagnetic-paramagnetic phase transition in magnetic semiconductors

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.

Hg1-xCoxSe mixed crystals: new semimagnetic semiconductor

Results of infrared reflectivity (in the phonon and plasma edge spectral regions) and magnetic susceptibility investigations performed on Hg 1−x Co x Se samples corresponding to a wide range of the crystal compositions (0 < x < 0.05) are presented and discussed. The evidence of an acceptor character of Co impurity is shown. Antiferromagnetic interactions between Co 2+ are confirmed, effective exchange integral is estimated to be J d−d /k B = (− 61.3 ± 6.7) K

Magnetic Properties of Ge1−x−yMnxEuyTe Mixed Crystals

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.

Curie temperature control by band parameters tuning in Pb1-x-y-zMnxSnyEuzTe

We present the study of magnetic and transport properties of Pb1−x−y−zMnxSnyEuzTe. AC magnetic susceptibility measurements as well as transport characterization were performed. The obtained results indicate that the presence of two types of magnetic ions influences the magnetic properties of the investigated IV–VI semimagnetic semiconductor. Qualitative analysis and possible mechanisms of the substantial dependence of the Curie temperature on the Eu content are presented. The most likely reason of the observed Curie temperature behaviour is a strong dependence of the location of a heavy mass Σ band upon the alloy composition. Theoretical calculations in frame of simple models confirm this point.

Magnetic properties of Fe-based two-anion semimagnetic semiconductors

Abstract Ac magnetic susceptibility and magnetization of mixed-anion semimagnetic semiconductor Cd 1- x Fe x Te 1- y Se y is successfully described in terms of the Curie-like contribution (specific for the Fe ions in mixed-anion environment of symmetry reduced to C 3v ) superimposed on Van Vleck paramagnetism (characteristic of the Fe ions in a higher symmetry environment).