Neutron diffraction study of the carrier-concentration-induced ferromagnet to spin glass transition in the diluted magnetic semiconductor Sn(1-x)Mn(x)Te

摘要

In the diluted magnetic semiconductor Sn(sub 1-x)Mn(sub x)Te; the charge carrier concentration p is of crucial importance for the low-temperature magnetic behavior. By means of neutron diffraction experiments, in combination with ac-susceptibility, magnetization, and specific heat data, we show that for x=0.04 the long-range-ordered ferromagnetic state observed for p=7x10(sup 20) cm(sup -3) gradually evolves into a spin-glass state with increasing carrier concentration. In a crystal with p=11x10(sup 20) cm(sup -3) initially a transition to a restricted-ranged ferromagnetic order occurs when the temperature is lowered in zero field, followed by a transition to a reentrant spin-glass phase. By the application of a small magnetic field (5.0 mT) the reentrant spin glass transition is suppressed. In a p=23x10(sup 20) cm(sup -3) crystal a spin glass phase is entered directly from the paramagnetic regime. The neutron diffraction results indicate the presence of short-range ferromagnetic fluctuations in this sample. The results are discussed in the context of an RKKY model. A three dimensional (T, x, p) magnetic phase diagram is presented. (orig.) (ERA citation 19:033577)