Quest to deliver ultra-fast and energy efficient magnetic recording
moves step closer

Date:
December 9, 2021
Source:
University of Exeter
Summary:
The quest to deliver ultra-fast and energy efficient magnetic
recording could be a step closer to fruition, due to pioneering
new research on all-optical switching of magnetization.



FULL STORY ==========================================================================
The quest to deliver ultra-fast and energy efficient magnetic recording
could be a step closer to fruition, due to pioneering new research on all-optical switching of magnetization.


==========================================================================
As the capacity and electricity consumption of data centres increases exponentially, there is a pressing economic and societal need to find
more energy efficient methods of information storage.

This demand has spurred extensive research effort into new physical
mechanisms for control of magnetization within magnetic thin films,
e.g., all-optical switching.

The all-optical switching of magnetization allows magnetic bits to be
written purely by optical laser pulses without any need for an external magnetic field.

Previous studies of all-optical switching of magnetization have almost exclusively focused on rare-earth based materials such as Gd and Tb,
which limits the tunability and scalability of the device.

A team of researchers, led by the University of Exeter, has made a pivotal breakthrough in the all-optical switching of magnetization, demonstrating
the potential to deliver energy efficient nanoscale magnetic storage
devices based solely on transition metals such as Fe, Co or Ni.

From the viewpoint of technological applications, the rare-earth free
synthetic ferrimagnets used in this work are highly desirable due to
the low cost and relative abundance of the constituent materials, and
the unparalleled tunability.

The results demonstrate that the all-optical switching is driven
by a spin- polarized current flowing between the two equivalent
magnetic configurations with antiparallel alignment of the Ni3Pt and
Co ferromagnetic layers. The switching can be achieved independently of
the light polarization and over a broad temperature range.

The research is published in Nano Letters.

Maciej D?browski, first author from the University of Exeter said: "Our
results demonstrate that the key ingredient for helicity independent all-optical switching in rare-earth free synthetic ferrimagnet is to
have two distinct transition metal layers.

By employing Ni3Pt and Co layers we were able to create an imbalance of
spin- polarized current for one trillionth of a second (10-12 s) after the laser excitation, which ultimately leads to the magnetization switching." ========================================================================== Story Source: Materials provided by University_of_Exeter. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Maciej Da̧browski, Jade N. Scott, William R. Hendren, Colin M.

Forbes, Andreas Frisk, David M. Burn, David G. Newman, Connor
R. J. Sait, Paul S. Keatley, Alpha T. N'Diaye, Thorsten Hesjedal,
Gerrit van der Laan, Robert M. Bowman, Robert J. Hicken. Transition
Metal Synthetic Ferrimagnets: Tunable Media for All-Optical
Switching Driven by Nanoscale Spin Current. Nano Letters, 2021;
21 (21): 9210 DOI: 10.1021/ acs.nanolett.1c03081 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/12/211209142531.htm

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