Magnetic properties of the diluted magnetic semiconductorZn1−xFexSe

The magnetic specific heat and low-field ac susceptibility of the iron-based diluted magnetic semiconductor (DMS) ${\mathrm{Zn}}_{1\mathrm{-}\mathrm{x}}$ ${\mathrm{Fe}}_{\mathrm{x}}$Se in the temperature range 0.4–20 K are reported. Antiferromagnetic d-d interactions and indications of spin-glass freezing are observed. These data, together with high-temperature susceptibility and high-field magnetization, are interpreted in the extended nearest-neighbor pair approximation, with an antiferromagnetic exchange between the ${\mathrm{Fe}}^{2+}$ ions. Fair agreement between theory and experiment is obtained for all the thermodynamic quantities with one set of parameters provided by independent experiments. The strength and range of the interactions, as well as the freezing mechanisms, are compared with DMS’s containing ${\mathrm{Mn}}^{2+}$, and the results are discussed in relation with the existing models.