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Group Seminar 2019/20

Category
Group Seminar
Date
Date
Wednesday 9 October 2019, 14:00-15:00
Location
EC Stoner (7.70)
Speaker
Dr Chiara Ciccarelli
Institution
Cavendish Laboratory at the University of Cambridge
Title
Picosecond spin emission from antiferromagnets and ferrimagnets

The transfer of the magnetic information via spin currents is one of the building blocks of spintronics.  This flow of angular momentum is enacted by spin-polarised charge currents in conductors and by pure spin-waves in insulators. Anti-ferromagnets have recently attracted much attention in spintronics for their favourable characteristics in the context of information storage technologies, such as fast switching times and zero stray fields. In anti-ferromagnets the magnetic moments are arranged in such a way to result in an overall zero magnetisation and it is an open question whether they can still act as efficient spin-emitters. In this talk I will describe the picosecond spin emission from a zero net-magnetisation spin source.  In the first experiment, I will discuss how lattice sensitive optical excitation of spin polarised carriers in a disordered ferrimagnetic alloy with a compensation point leads to spin emission even when the overall magnetisation is zero. The second work is about spin pumping from an anti-ferromagnet by which the excitation of coherent modes at 1.2 THz results in the emission of a pure spin-current.