scholarly journals Thickness-dependent electronic structure modulation of ferromagnetic films on shape memory alloy substrates based on a pure strain effect

2016 ◽  
Vol 109 (21) ◽  
pp. 212401 ◽  
Author(s):  
Chun Feng ◽  
Di Hu ◽  
Kui Gong ◽  
Xumin Jiang ◽  
Jianjuan Yin ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Strain Effect ◽  
Pure Strain ◽  
Ferromagnetic Films ◽  
Structure Modulation

scholarly journals Nonvolatile modulation of electronic structure and correlative magnetism of L10-FePt films using significant strain induced by shape memory substrates

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Chun Feng ◽  
Jiancheng Zhao ◽  
Feng Yang ◽  
Kui Gong ◽  
Shijie Hao ◽  
...  
Keyword(s):  
Shape Memory ◽  
Elastic Strain ◽  
Lattice Strain ◽  
Physical Nature ◽  
Strain Engineering ◽  
Strain Effect ◽  
Pure Strain ◽  
Electronic Density ◽  
Fept Film ◽  
Novel Approach

Abstract Tuning the lattice strain (εL) is a novel approach to manipulate the magnetic, electronic and transport properties of spintronic materials. Achievable εL in thin film samples induced by traditional ferroelectric or flexible substrates is usually volatile and well below 1%. Such limits in the tuning capability cannot meet the requirements for nonvolatile applications of spintronic materials. This study answers to the challenge of introducing significant amount of elastic strain in deposited thin films so that noticeable tuning of the spintronic characteristics can be realized. Based on subtle elastic strain engineering of depositing L10-FePt films on pre-stretched NiTi(Nb) shape memory alloy substrates, steerable and nonvolatile lattice strain up to 2.18% has been achieved in the L10-FePt films by thermally controlling the shape memory effect of the substrates. Introduced strains at this level significantly modify the electronic density of state, orbital overlap and spin-orbit coupling (SOC) strength in the FePt film, leading to nonvolatile modulation of magnetic anisotropy and magnetization reversal characteristics. This finding not only opens an efficient avenue for the nonvolatile tuning of SOC based magnetism and spintronic effects, but also helps to clarify the physical nature of pure strain effect.

A uniaxial constitutive model for NiTi shape memory alloy bars considering the effect of residual strain

2019 ◽  
Vol 30 (8) ◽  
pp. 1163-1177
Author(s):  
Canjun Li ◽  
Zhen Zhou ◽  
Yazhi Zhu
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Residual Strain ◽  
Hysteretic Behavior ◽  
Niti Shape Memory Alloy ◽  
Strain Effect ◽  
Proposed Model ◽  
Residual Strains

Super-elastic shape memory alloys are widely used in structural engineering fields due to their encouraging super-elasticity and energy dissipation capability. Large-size shape memory alloy bars often present significant residual strains after unloading, which emphasizes the necessity of developing a residual strain effect–coupled constitutive model to predict well the performance of shape memory alloy–based structures. First, this article experimentally studies the hysteretic behavior of NiTi shape memory alloy bars under quasi-static loading conditions and investigates the effects of cyclic numbers and strain amplitudes on residual strain. Second, a concept of cumulative transformation strain is preliminarily introduced into a phenomenological Lagoudas model. A uniaxial constitutive model for shape memory alloy bars including the residual strain is proposed. By using OpenSees platform, numerical simulations of shape memory alloy bars are conducted—the results of which indicate that the proposed model can accurately capture the hysteretic behavior of shape memory alloys. The predicted residual strains show a good agreement to experimental results, which demonstrates the desirable efficiency of the proposed model.

scholarly journals Nonlinear Model of Pseudoelastic Shape Memory Alloy Damper Considering Residual Martensite Strain Effect

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Y. M. Parulekar ◽  
G. R. Reddy
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Numerical Study ◽  
Large Strains ◽  
Strain Effect ◽  
Hysteretic Model ◽  
The Past ◽  
Proposed Model ◽  
Made In

Recently, there has been increasing interest in using superelastic shape memory alloys for applications in seismic resistant-design. Shape memory alloys (SMAs) have a unique property by which they can recover their original shape after experiencing large strains up to 8% either by heating (shape memory effect) or removing stress (pseudoelastic effect). Many simplified shape memory alloy models are suggested in the past literature for capturing the pseudoelastic response of SMAs in passive vibration control of structures. Most of these models do not consider the cyclic effects of SMA's and resulting residual martensite deformation. Therefore, a suitable constitutive model of shape memory alloy damper which represents the nonlinear hysterical dynamic system appropriately is essential. In this paper a multilinear hysteretic model incorporating residual martensite strain effect of pseudoelastic shape memory alloy damper is developed and experimentally validated using SMA wire, based damper device. A sensitivity analysis is done using the proposed model along with three other simplified SMA models. The models are implemented on a steel frame representing an SDOF system and the comparison of seismic response of structure with all the models is made in the numerical study.

scholarly journals Unoccupied electronic structure of Ni2MnGa ferromagnetic shape memory alloy

2015 ◽  
Vol 222 ◽  
pp. 1-4 ◽  
Author(s):  
M. Maniraj ◽  
S.W. D׳Souza ◽  
Abhishek Rai ◽  
D.L. Schlagel ◽  
T.A. Lograsso ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Ferromagnetic Shape Memory Alloy ◽  
Ferromagnetic Shape Memory

Structure and mobility of martensite variant interfaces in a Cu-Zn-AI shape memory alloy

2003 ◽  
Vol 112 ◽  
pp. 519-522 ◽  
Author(s):  
W. Cai ◽  
J. X. Zhang ◽  
Y. F. Zheng ◽  
L. C. Zhao
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Martensite Variant
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