Room-temperature magnetoresistance in an oxide material with an ordered double-perovskite structure
Room-temperature magnetoresistance in an oxide material with an ordered double-perovskite structure
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DOI：
10.1038/27167
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发表时间：
1998-10-15
期刊：
影响因子：
64.8
通讯作者：
Tokura, Y
中科院分区：
文献类型：
--
作者：
Kobayashi, KL;Kimura, T;Tokura, Y
巨磁阻效应是指在磁场作用下电阻的大幅降低，最近在具有钙钛矿结构的锰氧化物中被观察到。从基本和实际的观点来看，这种效应都引起了相当大的兴趣（1）。在实际器件中使用这种效应的背景下，这些材料的一个值得注意的特征是电荷载流子的高度自旋极化，这是由这些材料（20，21）的半金属性质引起的;这在原则上允许自旋相关的载流子散射过程，因此电阻受到低磁场的强烈影响。这种类型的场控制已经被证明用于隧道结（2，3）和晶体孪晶或陶瓷晶界（4，5）处的电荷载流子散射，尽管这种结构的操作温度对于大多数应用来说仍然太低（小于或等于150 K）。本文报道了一种有序双钙钛矿结构的材料Sr_2FeMoO_6在室温下表现出本征隧穿型磁电阻效应。我们解释了这种行为的起源与电子结构计算表明材料是半金属。我们的研究结果表明，在室温下可操作的有序钙钛矿磁阻器件的发展前景。
Colossal magnetoresistance-a huge decrease in resistance in response to a magnetic field-has recently been observed in manganese oxides with perovskite structure. This effect is attracting considerable interest from both fundamental and practical points of view(1). In the context of using this effect in practical devices, a noteworthy feature of these materials is the high degree of spin polarization of the charge carriers, caused by the half-metallic nature of these materials(20,21); this in principle allows spin-dependent carrier scattering processes, and hence the resistance, to be strongly influenced by low magnetic fields. This type of field control has been demonstrated for charge-carrier scattering at tunnelling junctions(2,3) and at crystal-twin or ceramic grain boundaries(4,5), although the operating temperature of such structures is still too low (less than or equal to 150K) for most applications. Here we report a material-Sr2FeMoO6, an ordered double perovskite(6)-exhibiting intrinsic tunnelling-type magnetoresistance at room temperature. We explain the origin of this behaviour with electronic-structure calculations that indicate the material to be half-metallic. Our results show promise for the development of ordered perovskite magnetoresistive devices that are operable at room temperature.