1. Spin reorientation in the Er 2-x Fe 14+2x Si 3 single-crystal studied by Mössbauer spectroscopy J. Żukrowski 1, A. Błachowski 2, K. Ruebenbauer 2, J. Przewoźnik 1, D. Sitko 3, N.-T.H. Kim-Ngan 3, Z. Tarnawski 1, A.V. Andreev 4 1 Solid State Physics Department, Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków, Poland 2 Mössbauer Spectroscopy Division, Institute of Physics, Pedagogical University, Kraków, Poland 3 Surface Physics Division, Institute of Physics, Pedagogical University, Kraków, Poland 4 Institute of Physics, Academy of Sciences, Prague, Czech Republic

2. Bulk magnetic moment versus temperature in the moderate external field 0.1 T aligned along the c-axis Er 2-x Fe 14+2x Si 3 single-crystal

3. Magnetic susceptibility versus temperature for various AC frequencies in the null external field and for the moderate external field 0.1 T applied along the c-axis. The AC field was applied along the c-axis. Er 2-x Fe 14+2x Si 3

4. K. Ruebenbauer, Physica B 172, 346 (1991)

5. Er 2-x Fe 14+2x Si 3 powder sample

6. verage angle between c-axis and iron hyperfine fields 0.5 Er 2-x Fe 14+2x Si 3 single-crystal

7. 4f 6g 12j or 12k 12k or 12j 2b 4e Contribution from iron atoms with hyperfine field perpendicular to c-axis Contribution (at. % Fe)

8. Er 2-x Fe 14+2x Si 3 Conclusions Spin reorientation from the [a - b] plane onto the c-axis occurs for all iron sub-lattices except for iron dumbbells substituting erbium (2b) in the temperature range 130 – 80 K due to the domain flip mechanism. Spin reorientation is less perfect for the sub-lattices (12j) and (12k) containing silicon. Gradual second spin reorientation occurs below 50 K leading to the partial recovery of the high temperature spin structure.