Spontaneous behavior and magnetic field and pressure effects on La2/3Ca1/3MnO3 perovskite.
Spontaneous behavior and magnetic field and pressure effects on La2/3Ca1/3MnO3 perovskite.
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DOI：
10.1103/physrevb.54.1187
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发表时间：
1996-07
期刊：
影响因子：
--
通讯作者：
de Teresa JM;Ibarra;Blasco;García;Marquina;Algarabel;Arnold;Kamenev;Ritter;von Helmolt R
中科院分区：
文献类型：
--
作者：
de Teresa JM;Ibarra;Blasco;García;Marquina;Algarabel;Arnold;Kamenev;Ritter;von Helmolt R
研究了磁场和压强对${\mathrm{La}}_{2/3}$${\mathrm{Ca}}_{1/3}$${\mathrm{MnO}}_{3}$反常自发行为的影响。在磁场和压力下的电阻率和体积热膨胀，压力下的交流磁化率，磁致伸缩，磁阻和中子衍射测量，使我们能够确定该系统的相关潜在机制。在{\mathit{T}}_{\mathit{c}}$以上，中子测量揭示了短程铁磁关联，反常的体积热膨胀表明存在局域扭曲。这两个实验都支持在${\mathit{T}}_{\mathit{c}}$以上形成磁极化子。在{\mathit{T}}_{\mathit{c}}，该化合物经历了顺磁-铁磁转变，伴随着绝缘体-金属的转变，并伴随着电学和体积性质的异常。在{\mathit{T}}_{\mathit{c}以上，磁场和压力通过增强双交换作用而有利于导电。在{\mathit{T}}_{\mathit{c}}以下，磁场和压力以不同的方式有利于金属状态。版权所有：1996美国物理学会。
The effects of magnetic field and pressure on the unusual spontaneous behavior of ${\mathrm{La}}_{2/3}$${\mathrm{Ca}}_{1/3}$${\mathrm{MnO}}_{3}$ have been thoroughly investigated. Resistivity and volume thermal expansion, both under magnetic field and pressure, ac susceptibility under pressure, magnetostriction, magnetoresistance, and neutron diffraction measurements, have allowed us to determine the relevant underlying mechanisms in this system. Above ${\mathit{T}}_{\mathit{c}}$ the neutron measurements reveal short-range ferromagnetic correlations and the anomalous volume thermal expansion indicates that local distortions are present. Both experiments support the formation of magnetic polarons above ${\mathit{T}}_{\mathit{c}}$. At ${\mathit{T}}_{\mathit{c}}$ the compound undergoes a paramagnetic-ferromagnetic transition accompanied by an insulator-metal-like transition with anomalies in the electrical and volume properties. Above ${\mathit{T}}_{\mathit{c}}$ the magnetic field and the pressure favor electrical conduction by enhancing the double-exchange interaction. Below ${\mathit{T}}_{\mathit{c}}$ the metallic state is favored by the magnetic field and the pressure in a different way. \textcopyright{} 1996 The American Physical Society.