Ren Qingyong, Hutchison Wayne, Wang Jianli, Studer Andrew, Wang Guohua, Zhou Haidong, Ma Jie, Campbell Stewart J
School of Physics and Astronomy and Key Laboratory of Artificial Structures and Quantum Control, School of Physics and Astronomy , Shanghai Jiao Tong University , Shanghai 200240 , China.
School of Science , The University of New South Wales at the Australian Defence Force Academy , Canberra , Australian Capital Territory 2600 , Australia.
ACS Appl Mater Interfaces. 2019 May 15;11(19):17531-17538. doi: 10.1021/acsami.9b02772. Epub 2019 May 6.
Compounds that exhibit the unique behavior of negative thermal expansion (NTE)-the physical property of contraction of the lattice parameters on warming-can be applied widely in modern technologies. Consequently, the search for and design of an NTE material with operational and controllable qualities at room temperature are important topics in both physics and materials science. In this work, we demonstrate a new route to achieve magnetic manipulation of a giant NTE in (MnNi)CoGe via strong magnetostructural (MS) coupling around room temperature (∼275 to ∼345 K). The MS coupling is realized through the weak bonding between the nonmagnetic CoGe-network and the magnetic Mn-sublattice. Application of a magnetic field changes the NTE in (MnNi)CoGe significantly: in particular, a change of Δ L/ L along the a axis of absolute value 15290(60) × 10-equivalent to a -31% reduction in NTE-is obtained at 295 K in response to a magnetic field of 8 T.
表现出负热膨胀（NTE）独特行为的化合物——即晶格参数在升温时收缩的物理性质——可广泛应用于现代技术中。因此，寻找和设计一种在室温下具有可操作性和可控性的NTE材料是物理学和材料科学中的重要课题。在这项工作中，我们展示了一条通过在室温（约275至约345 K）附近的强磁结构（MS）耦合来实现对（MnNi）CoGe中巨大NTE进行磁操控的新途径。MS耦合是通过非磁性CoGe网络与磁性Mn亚晶格之间的弱键实现的。施加磁场会显著改变（MnNi）CoGe中的NTE：特别是，在295 K时，响应8 T的磁场，沿a轴获得了绝对值为15290(60)×10的ΔL/L变化——相当于NTE降低了31%。
