کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1804670 1024652 2007 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Double symmetry breaking and magnetic transitions in ErFe4Ge2
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم فیزیک ماده چگال
پیش نمایش صفحه اول مقاله
Double symmetry breaking and magnetic transitions in ErFe4Ge2
چکیده انگلیسی

We have revised the T-magnetic phase diagram of the compound ErFe4Ge2 based on a recent X-ray powder diffraction study and software development enabling a new approach to this complex situation. Special emphasis is given to the intermediate temperature (IT) range 20 K–TN,Tc below the double first-order magneto-elastic transition where the tetragonal high-temperature (HT) phase disproportionates into two distinct orthorhombic phases: P42/mnm (HT phase) TN,Tc=44 K→Cmmm   (majority low-temperature (LT) phase) q1=(0,12,0)+Pnnm (minority IT Phase) (q2=(0, qy, 0), qy≈2/11). The phase diagram comprises three distinct regions: the HT range TN,Tc–293 K where the tetragonal phase P42/mnm is stable, the IT range 20 K–TN, where the Cmmm and Pnnm phases coexist in strongly variable proportions and the LT range, 1.5–20 K, where Cmmm prevails. The Pnnm phase reaches its highest concentration (≈33%) around 30 K. We report on the multi-axial amplitude modulated incommensurate magnetic structure of the Pnnm phase with a 2D-canted Fe moment arrangement q2=(0, qy, 0) and on the coexisting Cmmm   3D-canted magnetic phase with q1=(0,12,0). The spin reorientation transitions occurring in the Cmmm phase relate to the various structural changes both arising from competing magneto-elastic mechanisms, involving the Er crystal field anisotropy the Er–Er, Er–Fe and Fe–Fe exchange interactions and their coupling to the lattice strain. The Er–Er and Er–Fe interactions are dominating in the LT Cmmm phase while the Fe–Fe and Er–Fe interactions prevail in the Pnnm phase.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetism and Magnetic Materials - Volume 310, Issue 1, March 2007, Pages 63–75
نویسندگان
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