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arXiv 0910.2544cond-mat.mtrl-sci
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无序bcc-Fe-Cr合金的德拜温度

Debye temperature of disordered bcc-Fe-Cr alloys

S. M. Dubiel, J. Cieslak, B. F. O. Costa

摘要:

本文根据80- 300 K温度范围内~(57)Fe穆斯堡尔谱中心位移的温度依赖关系,确定了Fe_(100-x)Cr_x(0<x<99.9)无序合金的德拜温度TD。它的成分依赖性表现出一种有趣的非单调行为。对于0<x<~45以及~75<x<~95,德拜温度相对于金属铁的德拜温度值有所提高,并且在x=~3处存在局部最大值,其相对高度为纯铁的~12%。对于~45<x<~75和x>~95,德拜温度小于金属铁的德拜温度,在x=~55处有一个局部最小值,此时TD的相对降低量为~ 12%。第一个最大值与自旋波刚度系数D 0的最大值非常吻合,而在x>~95时观察到的相当陡峭的下降,这表明探针Fe原子与底层铬基体去耦,这可能与构成该组成区间内铬磁结构的自旋密度波有关。根据铁浓度最低的合金(x>99.9)的德拜温度计算的谐波力常数仅为纯铬的23%。

英文摘要:

Debye temperature, TD, of Fe100-xCrx disordered alloys with 0<x<99.9 was determined from the temperature dependence of the centre shift of 57Fe Mossbauer spectra recorded in the temperature range of 80-300K. Its compositional dependence shows an interesting non-monotonous behaviour. For 0<x<~45 as well as for ~75<x<~95 the Debye temperature is enhanced relative to its value of a metallic iron, and at x=~3 there is a local maximum having a relative height of ~12% compared to a pure iron. For ~45<x<~75 and for x>~95 the Debye temperature is smaller than the one for the metallic iron, with a local minimum at x=~55 at which the relative decrease of TD amounts to ~12%. The first maximum coincides quite well with that found for the spin-waves stiffness coefficient, D0, while the pretty steep decrease observed for x>~95 which is indicative of a decoupling of the probe Fe atoms from the underlying chromium matrix is likely related to the spin-density waves which constitute the magnetic structure of chromium in that interval of composition. The harmonic force constant calculated from the Debye temperature of the least Fe-concentrated alloy (x>99.9) amounts to only 23% of the one characteristic of a pure chromium.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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