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This article reports on the structure of the glassy system x CuO–65TeO 2 –(35− x )V 2 O 5 , 5≤ x ≤10 mol% which was studied using infrared (IR) and Raman spectroscopy methods as well as magnetic susceptibility measurements. IR and Raman spectroscopy analysis reveals the presence of four main absorption bands attributed to [TeO 3 ], [TeO 4 ], [VO 4 ], and [VO 5 ] structure units. It suggests that Cu 2+ ions occupy the available open spaces of the Te–O network without straining the bonds too much. Increasing the concentration of Cu 2+ ions beyond 5 mol% results in the modification of the glass by straining and locally distorting the surrounding of the Te–O network. The magnetic susceptibility of these materials was investigated in the temperature range of 5–200 K revealing the paramagnetic behavior described by the Curie–Weiss law and indicating the presence of weak antiferromagnetic exchange interactions between Cu ions. The magnetic entropy change of the glasses was determined based on the temperature and magnetic field dependence of magnetization.

Thin layers of semimagnetic (diluted magnetic) Sn1−xMnxTe semiconductor with Mn content x⩽0.04 and layer thickness 0.2 – 2 μm were grown by molecular beam epitaxy (MBE) on BaF2 (1 1 1) substrates with SnTe buffer layer. Apart from SnTe and Mn fluxes, we employed an additional Te flux to provide the efficient way of controlling the deviation from stoichiometry in the layers. By manipulating the MBE growth conditions we obtained SnMnTe crystalline layers with the conducting hole concentration in the range from p=5×10 19 cm −3 (no extra Te flux) to p=2×10 21 cm −3 (additional Te flux present). In the layers grown under extra Te flux conditions we observe ferromagnetic transition with the Curie temperature T C ⩽6 K (depending on both x and p). Layers with the same Mn content but grown with no extra Te flux are paramagnetic. This dramatic change of magnetic properties, referred to as a carrier concentration-induced ferromagnetic transition, can be understood in the framework of a model attributing the ferromagnetic interactions in SnMnTe to the mechanism of indirect exchange via conducting holes (Ruderman–Kittel–Kasuya–Yosida interaction).

It is expected that joint existence of ferromagnetic properties and ferroelectric structural phase transition in diluted magnetic semiconductors IV–VI leads to new possibilities of these materials. Temperature of ferroelectric transition for such crystals can be tuned by the change of Sn/Ge ratio. Magnetic susceptibility, Hall effect, resistivity and thermoelectric power of Ge 1− x − y Sn x Mn y Te single crystals grown by Bridgeman method ( x =0.083–0.115; y =0.025–0.124) were investigated within 4.2–300 K. An existence of FM ordering at T C ∼50 K probably due to indirect exchange interaction between Mn ions via degenerated hole gas was revealed. A divergence of magnetic moment temperature dependences at T ⩽ T C in field-cooled and zero-field-cooled regimes is obliged to magnetic clusters which are responsible for superparamagnetism at T > T C ≈ T f (freezing temperature) and become ferromagnetic at T C arranging spin glass state at T T f ≈ T C . Phase transition of ferroelectric type at T ≈46 K was revealed. Anomalous Hall effect which allows to determine magnetic moment was observed.

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).