Room-temperature antiferromagnetic memory resistor
Room-temperature antiferromagnetic memory resistor
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DOI：
10.1038/nmat3861
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发表时间：
2014-04-01
期刊：
影响因子：
41.2
通讯作者：
Ramesh, R.
中科院分区：
文献类型：
--
作者：
Marti, X.;Fina, I.;Ramesh, R.
铁磁体中有序自旋态的双稳性为磁记忆功能提供了基础。最新一代的磁性随机存取存储器依赖于一种有效的方法，即用电手段代替磁场来读写铁磁体中的信息。这一概念可能最终降低铁磁体对磁场扰动的敏感性，使其成为数据保留的弱点，并使铁磁体杂散场成为高密度存储器集成的障碍。本文报道了一种室温双稳态反铁磁（AFM）存储器，该存储器产生的杂散场可以忽略不计，并且对强磁场不敏感。我们使用了一个由FeRh AFM制成的电阻器，它的铁磁顺序大约在室温以上100 K，因此允许我们通过外加磁场设置不同的铁矩集体方向。在冷却至室温时，AFM顺序与高温铁磁状态下由场和力矩方向决定的AFM力矩方向一致。对于电读数，我们使用AFM模拟各向异性磁电阻。我们的微观理论模型证实，这种150多年前在铁磁体中发现的典型自旋电子效应也存在于原子力显微镜中。我们的工作证明了用原子力显微镜制造室温自旋电子存储器的可行性，这反过来又扩大了可用磁性材料的基础，用于具有铁磁体无法实现的性能的器件。
The bistability of ordered spin states in ferromagnets provides the basis for magnetic memory functionality. The latest generation of magnetic random access memories rely on an efficient approach in which magnetic fields are replaced by electrical means for writing and reading the information in ferromagnets. This concept may eventually reduce the sensitivity of ferromagnets to magnetic field perturbations to being a weakness for data retention and the ferromagnetic stray fields to an obstacle for high-density memory integration. Here we report a room-temperature bistable antiferromagnetic (AFM) memory that produces negligible stray fields and is insensitive to strong magnetic fields. We use a resistor made of a FeRh AFM, which orders ferromagnetically roughly 100 K above room temperature, and therefore allows us to set different collective directions for the Fe moments by applied magnetic field. On cooling to room temperature, AFM order sets in with the direction of the AFM moments predetermined by the field and moment direction in the high-temperature ferromagnetic state. For electrical reading, we use an AFM analogue of the anisotropic magnetoresistance. Our microscopic theory modelling confirms that this archetypical spintronic effect, discovered more than 150 years ago in ferromagnets, is also present in AFMs. Our work demonstrates the feasibility of fabricating room-temperature spintronic memories with AFMs, which in turn expands the base of available magnetic materials for devices with properties that cannot be achieved with ferromagnets.