MnCoSi基合金室温可逆大磁致伸缩效应

Large Reversible Magnetostrictive Effect in MnCoSi-Based Alloys at Room Temperature

磁场诱导的相变是实现大磁致伸缩效应的一种有效途径。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。介绍了一种特殊的磁相变合金—MnCoSi基合金,由于具有特殊的三相临界行为,MnCoSi基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。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。

It is found that the large magnetostrain can be obtained from the magnetic-field induced first-order transition in some magnetic-phase alloys. However, due to the first-order nature of the transition, the observed magnetostrain is accompa- nied 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 criti- cal 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.