Scientists at Tohuku university and the Semiconductor Spintronics Project of the Japan Science and Technology Corporation have been studying the use of electric fields to enable magnetisation reversal in ferromagnetic semiconductors (Sciencexpress report, July 10, 2003, 10.1126/science.1086608).

Scientists at Tohuku university and the Semiconductor Spintronics Project of the Japan Science and Technology Corporation have been studying the use of electric fields to enable magnetisation reversal in ferromagnetic semiconductors (Sciencexpress report, July 10, 2003, 10.1126/science.1086608).

The field effect experiments were performed on the ferromagnetic semiconductor manganese-doped indium arsenide (In,Mn)As. The material was incorporated as the channel layer in a metal-insulator-semiconductor field effect transistor (FET). By changing the sign of the electric field of 1.5MV/cm, the magnetic field required to reverse the material's magnetisation at 40K changed by a factor of five (from 1.0mT to 0.2mT).

Such studies could find application in magnetic memory. To achieve nanoscale bits, the magnetic energy density of the material has to be increase to ensure stability against thermal fluctuation. However, a high magnetic energy density increases the magnetic field needed to reverse the magnetisation. Applying an electric field could reduce the magnetic field needed to write data.

Raising such possibilities to room temperature (around 300K) is a major challenge. Ferromagnetism in thin-film semiconductors has been seen up to 60K for (In,Mn)As and up to 160K in (Ga,Mn)As. Theoretical considerations suggest that room temperature ferromagnetism could be reached by increasing Mn concentrations by a factor of two for (Ga,Mn)As and a factor of five for (In,Mn)As. Such concentrations have not been realised experimentally due to defects and the formation of an MnAs phase that reduces Mn concentrations in the host.

AngelTech Live III: Join us on 12 April 2021!

AngelTech Live III will be broadcast on 12 April 2021, 10am BST, rebroadcast on 14 April (10am CTT) and 16 April (10am PST) and will feature online versions of the market-leading physical events: CS International and PIC International PLUS a brand new Silicon Semiconductor International Track!

Thanks to the great diversity of the semiconductor industry, we are always chasing new markets and developing a range of exciting technologies.

2021 is no different. Over the last few months interest in deep-UV LEDs has rocketed, due to its capability to disinfect and sanitise areas and combat Covid-19. We shall consider a roadmap for this device, along with technologies for boosting its output.

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Additional areas we will cover include the development of GaN ICs, to improve the reach of power electronics; the great strides that have been made with gallium oxide; and a look at new materials, such as cubic GaN and AlScN.

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