Homogeneous limit of Cd1−xMnxGeAs2 alloy: Electrical and magnetic properties

• Published in: Journal of applied physics 2014-04, Vol.115 (13)
• Main Authors: Kilanski, L, Górska, M, Dynowska, E, Podgórni, A, Avdonin, A, Dobrowolski, W, Fedorchenko, I V, Marenkin, S F
• Format: Article
• Language: English
• Subjects: Applied physics; Crystal structure; Crystallography; Curie temperature; Curie-Weiss law; Diffraction patterns; Magnetic permeability; Magnetic properties; Manganese; Organic chemistry; Valence band
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4870474

We present the studies of structural, electrical, and magnetic properties of bulk Cd1−xMnxGeAs2 crystals with low Mn content, x, varying from 0 to 0.037. The studied samples have excellent crystallographic quality indicated by the presence of diffraction patterns never before observed experimentally for this compound. The electrical transport in our samples is dominated by thermal activation of conducting holes from the impurity states to the valence band with activation energy of about 200 meV. The defect states acting as ionic scattering centers with concentration in the range from 6 to 15 × 1017 cm−3 are observed. The effective Mn content in our samples, x¯θ, determined from fit of the susceptibility data to the Curie-Weiss law, is very close to the average chemical content, x. It indicates that the Mn ions are distributed randomly, substituting the Cd sites in the host CdGeAs2 lattice. We observe a negative Curie-Weiss temperature, |θ|≤3.1 K, increasing as a function of x. This indicates the significance of the short-range interactions between the Mn ions.