We present the studies of electrical transport and magnetic interactions in Zn 1− x Mn x GeAs2 crystals with low Mn content . We show that the ionic-acceptor defects are mainly responsible for the strong p-type conductivity of our samples. We found that the negative magnetoresistance with maximum values of about −50% is related to the weak localization phenomena. The magnetic properties of Zn 1− x Mn x GeAs2 samples show that the random Mn-distribution in the cation sites of the host lattice occurs only for the sample with the lowest Mn-content, x = 0.003. The samples with higher Mn-content show a high level of magnetic frustration. Nonzero Curie-Weiss temperature observed in all our samples indicates that weak ferromagnetic (for x = 0.003) or antiferromagnetic (for ) interactions with the Curie-Weiss temperature, , are present in this system. The Ruderman-Kittel-Kasuya-Yosida model, used to estimate the Mn-hole exchange integral Jpd for the diluted Zn 0.997Mn0.003GeAs2 sample, makes possible to estimate the value of .
Scientific work was financed from funds for science in 2011-2014, under the Project No. N202 166840 granted by the National Center for Science of Poland. This work has been supported by the RFBR Projects Nos. 12-03-31203 and 13-03-00125.
This work has been supported by the Polish Ministry of Science and Higher Education on a special purpose grant to fund the research and development activities and tasks associated with them, serving the development of young scientists and doctoral students.
I. INTRODUCTION A. Basic magnetotransport characterization A. Low field results II. BASIC CHARACTERIZATION B. High field magnetotransport B. High field results III. MAGNETOTRANSPORT DATA A. Basic magnetotransport characterization B. High field magnetotransport C. Electron paramagnetic resonance (EPR) IV. MAGNETIC PROPERTIES A. Low field results B. High field results C. Electron paramagnetic resonance (EPR) D. Curie-Weiss temperature and determination of Jpd V. SUMMARY