Böhmer A E, Sapkota A, Kreyssig A, Bud'ko S L, Drachuck G, Saunders S M, Goldman A I, Canfield P C
Ames Laboratory, US DOE, Ames, Iowa 50011, USA.
Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Phys Rev Lett. 2017 Mar 10;118(10):107002. doi: 10.1103/PhysRevLett.118.107002.
We study the effect of applied strain as a physical control parameter for the phase transitions of Ca(Fe_{1-x}Co_{x}){2}As{2} using resistivity, magnetization, x-ray diffraction, and ^{57}Fe Mössbauer spectroscopy. Biaxial strain, namely, compression of the basal plane of the tetragonal unit cell, is created through firm bonding of samples to a rigid substrate via differential thermal expansion. This strain is shown to induce a magnetostructural phase transition in originally paramagnetic samples, and superconductivity in previously nonsuperconducting ones. The magnetostructural transition is gradual as a consequence of using strain instead of pressure or stress as a tuning parameter.
我们使用电阻率、磁化强度、X射线衍射和57Fe穆斯堡尔谱，研究了外加应变作为Ca(Fe1-xCox)2As2相变物理控制参数的影响。通过样品与刚性衬底之间因热膨胀差异而牢固结合，产生双轴应变，即压缩四方晶胞的基面。结果表明，这种应变能在原本顺磁的样品中诱导磁结构相变，并在先前非超导的样品中诱导超导性。由于使用应变而非压力或应力作为调节参数，磁结构转变是渐进的。
