MnCoSi基合金室温可逆大磁致伸缩效应-中国材料进展

文章信息/Info

Title:: Large reversible magnetostrictive effect in MnCoSi-based alloys at room temperature

Author(s):: Si Yu; Liu Jun; Yang Hui; Gong Yuanyuan; Xu Feng; (School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China)

Keywords:: magnetostrictive effect; reversible; tricritical point; phase transition critical field

摘要:: 磁场诱导的相变是实现大磁致伸缩效应的一种有效途径。有别于传统磁致伸缩，该效应来源于相变过程伴随的晶格常数变化。然而，由于一级相变特征，磁致相变产生的磁致伸缩通常伴随较大的不可逆性，难以应用。本文将介绍一种特殊的磁相变合金MnCoSi。由于具有特殊的三相临界行为，MnCoSi合金有望在室温通过磁场诱导的二级相变实现可逆、低场的磁致伸缩效应。而上述效应的实现则依赖于合金三相临界行为的调控。通过调控，合金的三相点温度以及相变临界场降低，室温磁致伸缩效应源于磁场诱导的二级相变，可逆性提升。本文总结并介绍了调控机理以及部分调控方法，这些方法均能在相变临界场降低的前提下，实现室温可逆且较大的磁致伸缩效应。基于三相临界行为的调控，MnCoSi基合金有望具有媲美于Terfenol-D的磁致伸缩效应，在传感器、声纳、制动器以及震动马达等领域具有潜在的应用价值。

Abstract:: It is found that the large magnetostrain can be obtained from the magnetic-field induced first-order transition in some magnetic-phase alloys. The magnetostrain is generated from the lattice parameter alteration during the transition, which is quite different from that in conventional magnetostrictive alloys, such as Terfenol-D. However, due to the first-order nature of the transition, the observed magnetostrain is accompanied by obvious irreversibility. To overcome this drawback, we indicate that large reversible magnetostriction can be fulfilled in MnCoSi-based alloys at room temperature. By tuning tricritical behavior, the temperature of tricritical point and the critical driving field can be reduced. Based on this improvement, the room-temperature magnetostriction is generated from low-field induced second-order transition in MnCoSi-based alloys, which is characterized as high reversibility. We also introduce the mechanism and method of tricritical-behavior-tuning. The magnetostrictive effect in MnCoSi-based alloys is comparable to Terfenol-D, indicating potential applications in sensor, actuator, magnetomechanical relays, etc.