- Mgr. Denis Gorbunov: High-field magnetization and magnetoelasticity of single crystalline HoFe5Al7
- 6. 11. 2013, 14:00
- Seminar room KFM, first floor Ke Karlovu 5
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Abstract:
Magnetization and ultrasound measurements have been performed in pulsedmagnetic fields up to 60 T on a ferrimagnetic HoFe5Al7 single crystal(Curie temperature TC = 216 K, compensation point Tcomp = 65 K) with atetragonal crystal structure of the ThMn12-type. The compound exhibits ahigh magnetic anisotropy of the easy-plane type. A large anisotropy isalso observed within the basal plane having an easy-magnetizationdirection along the [110] axis with the spontaneous magnetic moment Ms = 2µB/f.u. at T = 2 K. Along the easy axis, two first-order field-inducedmagnetic transitions are observed. At both transitions sharp anomalies inthe acoustic properties are found. The critical fields of the transitionsdepend on temperature in a different manner. Within molecular-field theoryand using the high-field magnetization data the Ho-Fe inter-sublatticeexchange parameter has been determined to be nHoFe &≈ 4 T/µB. Themagnetoelasticity has also been probed by magnetization measurements underhydrostatic pressure. TC decreases with a rate dTC/dp = -10 K/GPa, whereasTcomp increases with dTcomp/dp = 3.5 K/GPa.