Ferromagnetism in new diluted magnetic semiconductor Si1-xMnxTe1.5 crystals

In this work, magnetic and electrical properties of the Si_1-xMn_xTe_1.5 (x=0.05, 0.11, 0.21, 0.31) diluted magnetic semiconductors and the effect of Mn-substitution are studied. XRD measurements of the samples reveal no impurity peaks and the lattice constants increase with Mn concentration, possibly due to the larger Mn atomic radius than Si. The magnetic and electrical properties of the samples are determined from superconducting quantum interference device (SQUID) magnetometry and magnetotransport measurements. Results show that magnetization of the samples increases with increasing Mn content. A transition to a state of long-range magnetic order is found at T_C = 82±2 K. Increasing Mn content (x>0.05) results in a ferromagnetic-paramagnetic transition around 280 K. At 250 K, magnetization loops indicate that the crystals are ferromagnets and the coercive field increases with increasing Mn concentration. Also, large magnetic moments observed in these crystals indicate that the spin-spin interaction is enhanced by the addition of Mn.