Laser ablation (LA) was used to cut an actuating element from a single crystal of a magnetic shape memory alloy NiMnGa. A thorough characterization of the structural, magnetic, and mechanical properties of the LA-cut sample was performed. The LA cutting stabilized a fine twin structure with type 1 twins in the five-layered modulated martensitic phase of the alloy at ambient temperature. The sample exhibited a magnetic-field-induced strain of 4.5 %, and a 1.02 MPa twinning stress which is 7 % more when compared to an untreated crystal with polysynthetic fine twins. The observed increase of the twinning stress and a moderate increase of the stress-strain loop slope point to surface defects originating from the LA cutting, which act as pinning points for twin boundaries. Due to the stabilized fine twin structure, the sample demonstrated superior properties in high-rate magnetic actuation, reaching an actuation velocity of more than 4 m/s.

中文翻译：

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通过激光烧蚀制造的磁性形状记忆驱动元件的表征

激光烧蚀 (LA) 用于从磁性形状记忆合金 NiMnGa 单晶上切割驱动元件。对 LA 切割样品的结构、磁性和机械性能进行了全面表征。LA 切削在环境温度下稳定了合金五层调制马氏体相中 1 型孪晶的精细孪晶结构。该样品表现出 4.5% 的磁场诱发应变和 1.02 MPa 的孪晶应力，与未经处理的多合成细孪晶晶体相比，该应力高出 7%。观察到的孪晶应力的增加和应力-应变环斜率的适度增加表明源自 LA 切削的表面缺陷，这些缺陷充当孪晶边界的钉扎点。由于稳定的精细孪晶结构，该样品在高速磁驱动中表现出优异的性能，驱动速度达到4 m/s以上。