Spin reorientation process in Tm_2–xHo_xFe₁₄B – analysis of conical arrangement based on Mössbauer spectra

Abstract

Abstract. The spin reorientation process in the Tm 2-x Ho x Fe 14 B series of compounds was studied using 57 Fe Mössbauer spectroscopy over the temperature range 5.2-320 K with a focus on the analysis of conical spin arrangement. Each compound was studied by precise Mössbauer scanning in the vicinity of the transition and during the transition. By applying computer simulations based on the simplifi ed Yamada-Kato model, as well as on some literature data for R 2 Fe 14 B (R = Tm, Ho) compounds, the above series was selected for studies as it contains compounds with different spin arrangements (axial, planar, conical). It was a crucial requirement for obtaining unambiguous angular dependences when applying a simultaneous fi tting procedure of Mössbauer spectra. Such an extended procedure was applied which allowed the temperature dependence of the angle describing the position of the magnetization vector to be obtained. The results were compared with those from theoretical simulations. The spin arrangement diagram was constructed. A conical spin arrangement was confi rmed over a wide temperature range.

From Flip to Slow Rotation-Spin Reorientation Process in Tm2-xTbxFe14B Observed by Mössbauer Spectroscopy

“…Our goal was to describe a path from planar to axial spin arrangements during spin reorientation process and to determine angles of conical arrangement by applying a procedure which was successfully used before for Er 2−x Ho x Fe 14 B and Tm 2−x Ho x Fe 14 B [7,11]. Additionally, a qualitative influence of α J on the process was of interest.…”