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MA: Fachverband Magnetismus

MA 35: Magnetic Oxides and Shape Memory Alloys (jointly with MM)

MA 35.3: Vortrag

Donnerstag, 14. März 2013, 10:00–10:15, H23

Unusual magnetic anisotropy of the ferromagnetic shape-memory alloy Ni₅₀Fe₂₃Ga₂₇ — •Jin-Feng Qian^1,2, Wen-Hong Wang¹, Guang-Heng Wu¹, and Claudia Felser² — ¹Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China — ²Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany

Unusual magnetic anisotropy of the ferromagnetic shape-memory alloy Ni₅₀Fe₂₃Ga₂₇ has been observed. The anisotropy of the austenite becomes very large, even larger than that of the martnsite in ribbon samples. Lowering the temperature from 300 K to 80 K, the saturation field of the austenite is dramatically increased from 200 Oe up to 6 kOe. This high-anisotropy clearly highlights the demagnetization effect of the martensitic transformation. The physical mechanism is attributed to a combined effect coming from the atomic disorder, the premartensitic transformation, and the off-stoichiometric Ga-rich composition of the alloys.