Ferromagnetic semiconductor Ge1−x−ySnxMnyTe with phase transformation of ferroelectric type

Abstract 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.