Salazar Mejía C, Nayak A K, Schiemer J A, Felser C, Nicklas M, Carpenter M A
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187 Dresden, Germany.
J Phys Condens Matter. 2015 Oct 21;27(41):415402. doi: 10.1088/0953-8984/27/41/415402. Epub 2015 Sep 29.
The lattice dynamics in the polycrystalline shape-memory Heusler alloy Ni50Mn35In15 have been studied by means of resonant ultrasound spectroscopy (RUS). RUS spectra were collected in a frequency range 100-1200 kHz between 10 and 350 K. Ni50Mn35In15 exhibits a ferromagnetic transition at 313 K in the austenite phase and a martensitic transition at 248 K accompanied by a change of the magnetic state. Furthermore it displays a paramagnetic to ferrimagnetic transition within the martensitic phase. We determined the temperature dependence of the shear modulus and the acoustic attenuation of Ni50Mn35In15 and compared it with magnetization data. Following the structural softening, which accompanies the martensitic transition as a pretransitional phenomenon, a strong stiffening of the lattice is observed at the martensitic magneto-structural transition. Only a weak magnetoelastic coupling is evidenced at the Curie temperatures both in austenite and martensite phases. The large acoustic damping in the martensitic phase compared with the austenitic phase reflects the motion of the twin walls, which freezes out in the low temperature region.
利用共振超声光谱法（RUS）研究了多晶形状记忆赫斯勒合金Ni50Mn35In15中的晶格动力学。在10至350 K的温度范围内，于100 - 1200 kHz的频率区间收集了RUS光谱。Ni50Mn35In15在奥氏体相中于313 K呈现铁磁转变，在248 K发生马氏体转变并伴随磁态变化。此外，它在马氏体相中还表现出顺磁到亚铁磁的转变。我们测定了Ni50Mn35In15的剪切模量和声学衰减随温度的变化，并将其与磁化数据进行了比较。随着作为预转变现象伴随马氏体转变出现的结构软化，在马氏体磁结构转变时观察到晶格的强烈硬化。在奥氏体和马氏体相的居里温度下，仅证明存在微弱的磁弹性耦合。与奥氏体相相比，马氏体相中的大声学阻尼反映了孪晶界的运动，这种运动在低温区域冻结。
