Magnetic Hyperfine Interactions of 57 Fe Probe Atoms in the CaCu x Mn 7 – x O 12 (0 ≤ x ≤ 1) Manganites

Magnetic and Mossbauer measurements are performed on the nuclei of 57Fe probe atoms in the structure of the substituted CaCuxMn6.96 – x57Fe0.04O12 (0 ≤ x ≤ 1) manganites in the magnetic-ordering temperature range T ≤ TN,C. The experimental results are used to analyze the exchange interactions and the possible magnetic-ordering configurations of cations with octahedral (Mn3+/Mn4+) and square (Cu2+/Mn3+) oxygen coordinations. The causes of the nonmonotonic change in the magnetic-ordering temperature TN,C(x) with composition x of the copper-substituted manganites are considered.