Negative Thermal Expansion in the Materials With Giant Magnetocaloric Effect.

Fengxia Hu,Jiazheng Hao,Yao Liu,Jing Wang,Jirong Sun,Feiran Shen,Baogen Shen

doi:10.3389/fchem.2018.00438

Abstract

Negative thermal expansion (NTE) behaviors in the materials with giant magnetocaloric effects (MCE) have been reviewed. Attentions are mainly focused on the hexagonal Ni2In-type MM'X compounds. Other MCE materials, such as La(Fe,Si)13, RCo2, and antiperovskite compounds are also simply introduced. The novel MCE and phase-transition-type NTE materials have similar physics origin though the applications are distinct. Spin-lattice coupling plays a key role for the both effect of NTE and giant MCE. Most of the giant MCE materials show abnormal lattice expansion owing to magnetic interactions, which provides a natural platform for exploring NTE materials. We anticipate that the present review can help finding more ways to regulate phase transition and dig novel NTE materials.

Highlights

Magnetic cooling technique based on magnetocaloric effect (MCE) has attracted an increasing attention for its environmental-friendly and energy-saving superiority compared to conventional vapor compression technique
Note that a number of MCE materials show abnormal lattice expansion owing to magnetic interactions, which provides a natural platform for exploring negative thermal expansion materials
MCE materials are used for magnetic refrigeration while negative thermal expansion (NTE) materials for thermal compensation

Summary

INTRODUCTION

Magnetic cooling technique based on magnetocaloric effect (MCE) has attracted an increasing attention for its environmental-friendly and energy-saving superiority compared to conventional vapor compression technique The introduced residual strain in the MnCoGe1−xInx thin slices prepared by cold pressing can stabilize the austenite phase, as a result, the temperature window of martensitic transformation is broadened, the magnetic and structural transition becomes decoupling (Liu et al, 2015). For the powder prepared by TC, the sample does not suffer any external pressure, and the introduced strain is weaker than the case by BM, leading to the completely different evolution of phase transition with temperature All these results suggest the TC or slightly BM treatments can both extend temperature interval and optimize the NTE properties, which have high potential applications as the PTE compensators by forming composites. The decrease of magnetization with temperature is responsible for the negative contribution to volume expansion, which neutralizes the normal lattice expansion, and produces the ZTE

A BRIEF INTRODUCTION ON

Findings

CONCLUSION