Confined spin waves reveal an assembly of nanosize domains in ferromagneticLa1-xCaxMnO3 (x=0.17,0.2).
Confined spin waves reveal an assembly of nanosize domains in ferromagneticLa1-xCaxMnO3 (x=0.17,0.2).
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受限自旋波揭示了铁磁 La1-xCaxMnO3 (x=0.17,0.2) 中纳米尺寸域的组装。
DOI：
10.1103/physrevlett.94.057006
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发表时间：
2004
影响因子：
8.6
通讯作者：
D. Shulyatev
中科院分区：
文献类型：
--
作者：
M. Hennion;F. Moussa;P. Lehouelleur;F. Wang;A. Ivanov;Y. Mukovskiǐ;D. Shulyatev
我们报道了铁磁性La_(1-x)Ca_xMnO_3中的自旋波的研究，当x=0.17时，x=0.2时，非常接近金属相变(x=0.225)。在T(C)以下，在准金属态(T=150K)下，观察到几乎与Q无关的能级。它们的特征是驻留自旋波被限制在有限大小的铁磁区中，当x=0.17时，仅在(a，b)平面内定义，当x=0.2时，在所有方向上定义。它们允许估计磁区的大小、几个晶格间距以及磁区内的磁耦合常数。这些各向异性的常数是典型的轨道有序状态，允许人们将这些区域描述为“空穴贫乏”。因此，巨磁阻金属相的前驱态表现为小的轨道有序磁区的集合。
We report a study of spin waves in ferromagnetic La1-xCaxMnO3, at concentrations x=0.17 and x=0.2 very close to the metallic transition (x=0.225). Below T(C), in the quasimetallic state (T=150 K), nearly q-independent energy levels are observed. They are characteristic of standing spin waves confined into finite-size ferromagnetic domains, defined only in the (a,b) plane for x=0.17, and in all directions for x=0.2. They allow an estimation of the domain's size, a few lattice spacings, and of the magnetic coupling constants inside the domains. These constants, anisotropic, are typical of an orbital-ordered state, allowing one to characterize the domains as "hole poor." The precursor state of the collossal magnetoresistance metallic phase appears, therefore, as an assembly of small orbital-ordered domains.