Phase diagram and magnetocaloric effects in aluminum doped MnNiGe alloys
Phase diagram and magnetocaloric effects in aluminum doped MnNiGe alloys
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DOI：
10.1063/1.4826260
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发表时间：
2013-10
影响因子：
3.2
通讯作者：
A. Quetz;Tampas Samanta;I. Dubenko;Michael J. Kangas;J. Chan;S. Stadler;N. Ali
中科院分区：
文献类型：
--
作者：
A. Quetz;Tampas Samanta;I. Dubenko;Michael J. Kangas;J. Chan;S. Stadler;N. Ali
MnNiGe 1 −xAlx系统的磁热和热磁性质已经通过变温X射线衍射、差示扫描量热法（DSC）和磁化强度测量进行了研究。在MnNiGe 1 −xAlx中，Al部分取代Ge导致在186 K（x = 0.09）下从六方铁磁相到正交反铁磁相的一级磁结构转变（MST）。在TM = 186 K（x = 0.09）附近观测到一个大的磁熵变，ΔH = 5 T时，ΔSM = −17.6 J/kg K。该值与诸如Gd 5Si 2Ge 2、MnFeP0.45As0.55和Ni 50 Mn 37 Sn 13的巨磁热材料的值相当。用DSC测量了MST的潜热（L = 6.6 J/g）和相应的总熵变（ΔST = 35 J/kg K）。当x = 0.09和0.085时，在TC附近，ΔH = 5 T时，ΔSM分别为−5.8和−4.8 J/kg K的大负值。浓度依赖的相变相图。
The magnetocaloric and thermomagnetic properties of the MnNiGe1−xAlx system have been studied by temperature-dependent x-ray diffraction, differential scanning calorimetry (DSC), and magnetization measurements. The partial substitution of Al for Ge in MnNiGe1−xAlx results in a first order magnetostructural transition (MST) from a hexagonal ferromagnetic to an orthorhombic antiferromagnetic phase at 186 K (for x = 0.09). A large magnetic entropy change of ΔSM = −17.6 J/kg K for ΔH = 5 T was observed in the vicinity of TM = 186 K for x = 0.09. The value is comparable to those of giant magnetocaloric materials such as Gd5Si2Ge2, MnFeP0.45As0.55, and Ni50Mn37Sn13. The values of the latent heat (L = 6.6 J/g) and corresponding total entropy changes (ΔST = 35 J/kg K) have been evaluated for the MST using DSC measurements. Large negative values of ΔSM of −5.8 and −4.8 J/kg K for ΔH = 5 T in the vicinity of TC were observed for x = 0.09 and 0.085, respectively. A concentration-dependent phase diagram of transition...