Researchers from the Institut de Ciència de Materials de Barcelona (ICMAB-CSIC) participate in a study, which has been published in Nature Communications and may open new possibilities for the integration of magnetic semiconductors in spintronics.
Researchers from the Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), in collaboration with scientist from other countries, discover the existence of large changes of the electric resistance of semiconducting materials when the direction of the magnetic moments of the constituting atoms is modified. This result, which has been published in Nature Communications, may open new possibilities for the integration of magnetic semiconductors in spintronics.
Current electronic devices rely on the modulation of the electric conductivity of semiconducting materials by electric fields. The electric conductivity of ferromagnetic semiconductors can also be modified by magnetic fields, promising new the opportunities to integrate magnetism in electronics with the added benefit of possible magnetic memory effects in semiconductors. However, in spite of the strenuous efforts, room-temperature ferromagnetic semiconductors appear to be elusive.
Here, it has been shown that antiferromagnetic semiconductors could step on the stage. It has been discovered that in suitable antiferromagnet semiconductors (Sr2IrO4), the electric resistivity can be largely modified by changing the direction of the atomic spins. It is shown that this effect is primarily related to modifications of the electronic structure of the semiconductor upon rotation of atomic spins: a subtle effect of relativistic origin that results from the coupling of atomic spins to atomic orbital momenta. Therefore different resistance states, say: HIGH/LOW or ON/OFF, can be induced in the material.
The next challenge is how to manipulate the spin direction in the antiferromagnet, which itself is rather insensitive to magnetic dipolar fields. Quantum physics holds the clue as magnetic exchange interactions across the interface between an ultrathin antiferromagnet semiconductor layer and and a metallic ferromagnet layer allows magnetic control of the former when applying a magnetic field to the latter. Therefore, the whole is more than the sum of its parts.
The recent results from ICMAB researchers and collaborators offer a new perspective on materials and device structures that may open new paths in spintronics by allowing integration of antiferromagnetic semiconductors in non-volatile memories and other gadgets.
Anisotropic magnetoresistance in anantiferromagnetic semiconductor I. Fina, X. Marti, D. Yi, J. Liu, J.H. Chu, C. Rayan-Serrao, S. Suresha, A.B. Shick, J. Zelezny, T. Jungwirth, J. Fontcuberta, R. Ramesh, Nature Communications 5, Article number: 4671; doi:10.1038/ncomms5671
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