Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
Phys Rev Lett. 2011 Dec 16;107(25):257201. doi: 10.1103/PhysRevLett.107.257201. Epub 2011 Dec 13.
Double perovskites such as Sr(2)FeMoO(6) are rare examples of materials with half-metallic ground states and a ferrimagnetic T(c) above room temperature. We present a comprehensive theory of the temperature and disorder dependence of their magnetic properties by deriving and validating a new effective spin Hamiltonian for these materials, amenable to large-scale three-dimensional simulations. We show how disorder, ubiquitous in these materials, affects T(c), the magnetization, and the conduction electron polarization. We conclude with a novel proposal to enhance T(c) without sacrificing polarization.
双钙钛矿如 Sr(2)FeMoO(6) 是少数具有半金属基态和室温以上铁磁共振温度的材料。我们通过为这些材料推导出和验证一个新的有效自旋哈密顿量，为其磁性质的温度和无序依赖性提供了一个全面的理论，该哈密顿量适用于大规模的三维模拟。我们展示了无序（这些材料中普遍存在的）如何影响 T(c)、磁化强度和传导电子极化。最后，我们提出了一种新颖的方案，在不牺牲极化的情况下提高 T(c)。
