scholarly journals Dependence of the Magnetization Process on the Thickness of Fe70Pd30 Nanostructured Thin Film

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5788
Author(s):  
Mohamed Salaheldeen ◽  
Ahmed Mohamed Abu-Dief ◽  
Lucía Martínez-Goyeneche ◽  
Seraj Omar Alzahrani ◽  
Fatmah Alkhatib ◽  
...  

Fe–Pd magnetic shape-memory alloys are of major importance for microsystem applications due to their magnetically driven large reversible strains under moderate stresses. In this context, we focus on the synthesis of nanostructured Fe70Pd30 shape-memory alloy antidot array thin films with different layer thicknesses in the range from 20 nm to 80 nm, deposited onto nanostructured alumina membranes. A significant change in the magnetization process of nanostructured samples was detected by varying the layer thickness. The in-plane coercivity for the antidot array samples increased with decreasing layer thickness, whereas for non-patterned films the coercive field decreased. Anomalous coercivity dependence with temperature was detected for thinner antidot array samples, observing a critical temperature at which the in-plane coercivity behavior changed. A significant reduction in the Curie temperature for antidot samples with thinner layer thicknesses was observed. We attribute these effects to complex magnetization reversal processes and the three-dimensional magnetization profile induced by the nanoholes. These findings could be of major interest in the development of novel magnetic sensors and thermo-magnetic recording patterned media based on template-assisted deposition techniques.

2011 ◽  
Vol 34 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Ferdinando Auricchio ◽  
Anne-Laure Bessoud ◽  
Alessandro Reali ◽  
Ulisse Stefanelli

2013 ◽  
Vol 738-739 ◽  
pp. 400-404 ◽  
Author(s):  
Yong Jun He ◽  
Xue Chen ◽  
Ziad Moumni

This paper explains the magnetic-field induced martensite reorientation in Ferromagnetic Shape Memory Alloys (FSMA) through a simple energy analysis from which the role of the martensite’s magnetic anisotropy is emphasized. In particularly, with a three-dimensional (3D) energy analysis, we study the switching between the three tetragonal martensite variants driven by a rotating magnetic field (with a constant magnitude) and a non-rotating magnetic field (with a fixed direction but varying magnitudes). Finally, a simple planar phase diagram is proposed to describe the martensite reorientation in general 3D loadings.


2011 ◽  
Vol 21 (05) ◽  
pp. 1043-1069 ◽  
Author(s):  
A.-L. BESSOUD ◽  
U. STEFANELLI

We present a three-dimensional phenomenological model for the magneto-mechanical behavior of magnetic shape memory materials such as Ni2MnGa . Moving from micromagnetic considerations, we advance to some thermodynamically consistent constitutive relations describing the magnetically-induced cubic-to-tetragonal martensitic transformation in a single crystal. We present an existence analysis for both the constitutive relation problem and the three-dimensional quasi-static evolution problem. Finally, we discuss the reduction of this model to some simpler one by means of a rigorous Γ-convergence analysis.


Author(s):  
Tianjiao Wang ◽  
Jun Zhao ◽  
Chuanxin Weng ◽  
Tong Wang ◽  
Yayun Liu ◽  
...  

Shape memory polymers (SMPs) that change shapes as designed by external stimuli have become one of the most promising materials as actuators, sensors, and deployable devices. However, their practical applications...


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