scholarly journals Effect of Co and Mn Doping on the Martensitic Transformations and Magnetic Properties of Fe-Pd Ferromagnetic Shape Memory Alloys

2009 ◽  
Vol 635 ◽  
pp. 103-110 ◽  
Author(s):  
Vicente Sánchez-Alarcos ◽  
José Ignacio Pérez-Landazábal ◽  
Vicente Recarte
Keyword(s):  
Magnetic Properties ◽  
Opposite Effect ◽  
Martensitic Transformations ◽  
Partial Substitution ◽  
Compositional Dependence ◽  
Ferromagnetic Shape Memory Alloys ◽  
Mn Doping ◽  
Structural And Magnetic Properties ◽  
Co Addition ◽  
Ferromagnetic Shape Memory

The effect of the partial substitution of Fe by Co and Mn on the structural and magnetic properties of Fe-Pd alloys has been investigated by means of calorimetric, magnetic and neutron diffraction measurements. The addition of Mn increases both the reversible and irreversible MT temperatures whereas the addition of Co causes the opposite effect, which points out that that the compositional dependence of the transformation temperatures of the Fe-Pd alloys is not related to the Pd amount but to the e/a concentration. Furthermore, it is shown that the appearance of the BCT phase is directly related to the tetragonality of the FCT phase. On the other hand, the amount of FCT martensite that irreversibly transforms into the undesirable BCT phase is considerably reduced by both the Co and Mn doping. The substitution of Fe by Co seems to be especially interesting for magnetic field-induce strains applications since both the magnetic anisotropy and the saturation magnetization of the Fe-Pd FCT martensite are considerably increased with the Co addition.

Effects of Co Addition on Crystal Structure, Thermal Stability and Magnetic Properties of Ni-Mn-Ga Ferromagnetic Shape Memory Alloys from First-Principles Calculations

2012 ◽  
Vol 706-709 ◽  
pp. 1990-1995
Author(s):  
Jing Bai ◽  
Jean Marc Raulot ◽  
Yu Dong Zhang ◽  
Claude Esling ◽  
Xiang Zhao ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Ferromagnetic Shape Memory Alloys ◽  
Electronic Density ◽  
Co Addition ◽  
Ferromagnetic Shape Memory

The effect of Co addition on the properties of Ni8-xMn4Ga4Cox(x=0, 0.5, 1, 1.5 and 2) ferromagnetic shape memory alloys are systematically investigated by means of the first–principles calculations within the framework of density functional theory (DFT) using the Viennaabinitiosoftware package (VASP). The formation energy results indicate that the added Co preferentially occupies the Ni sites in Ni2MnGa alloy. With the increase of the Co content, the optimized lattice parameters of the parent phase decreases regularly, whereas the lattice parameteraof the martensite increases andcdecreases, thus leading to a decrease of thec/aratio. The effects of Co addition on phase stability of the paramagnetic and ferromagnetic austenite are displayed. The difference in the magnetic properties in the investigated series can be explained from the electronic density of states analysis. The aim of this paper is to provide theoretical guidance for the development of new promising ferromagnetic shape memory alloys with optimized properties.

Influence of Long-Range Atomic Order on the Structural and Magnetic Properties of Ni-Mn-Ga Ferromagnetic Shape Memory Alloys

2011 ◽  
Vol 684 ◽  
pp. 85-103 ◽  
Author(s):  
Vicente Sánchez-Alarcos ◽  
José Ignacio Pérez-Landazábal ◽  
Vicente Recarte
Keyword(s):  
Magnetic Properties ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Long Range ◽  
Atomic Order ◽  
Ferromagnetic Shape Memory Alloys ◽  
Magnetic Exchange ◽  
Range Atomic Order ◽  
Structural And Magnetic Properties ◽  
Ferromagnetic Shape Memory

This chapter presents a review of the most recent and systematic works performed on the study of the effect of atomic order on the structural and magnetic properties of Ni-Mn-Ga ferromagnetic shape memory alloys. It is shown that a correlation between long-range atomic order and the martensitic and Curie temperatures can be established from the analysis of its evolution under high and low temperature thermal treatments. In particular, it is demonstrated that, irrespectively of the thermal treatment, both transformation temperatures increase with the increasing L21 atomic order degree, showing practically the same linear dependence on the nextnearest- neighbors atomic order parameter, in such a way that the effect of the atomic order on the relative stability between austenite and martensite can be quantitatively determined. In this respect, it is shown that the effect of atomic order on the martensitic (and also the premartensitic) transformation is directly related to the variation of the magnetic exchange coupling.

Effect of Mn addition on the structural and magnetic properties of Fe–Pd ferromagnetic shape memory alloys

2009 ◽  
Vol 57 (14) ◽  
pp. 4224-4232 ◽  
Author(s):  
V. Sánchez-Alarcos ◽  
V. Recarte ◽  
J.I. Pérez-Landazábal ◽  
M.A. González ◽  
J.A. Rodríguez-Velamazán
Keyword(s):  
Magnetic Properties ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Structural And Magnetic Properties ◽  
Ferromagnetic Shape Memory

Magnetic properties of ferromagnetic shape memory alloys Ni _{2-x} Cu _{x} MnGa

2005 ◽  
Vol 21 (3-4) ◽  
pp. 151-157 ◽  
Author(s):  
Takeshi Kanomata ◽  
Takuji Nozawa ◽  
Daisuke Kikuchi ◽  
Hironori Nishihara ◽  
Keiichi Koyama ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory
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