TY - JOUR
T1 - All Optical Switching
T2 - a Path to Recording Technology Beyond HAMR
AU - Strungaru, Mara
AU - Ruta, Sergiu
AU - Evans, Richard F.L.
AU - Barker, Joseph
AU - Yuanmae, Khanitta
AU - Chureemart, Jessada
AU - Chureemart, Phanwadee
AU - Rasing, Theo
AU - Chantrell, Roy W.
N1 - Publisher Copyright:
© 1965-2012 IEEE.
PY - 2025
Y1 - 2025
N2 - After 20 years of development heat assisted magnetic recording, HAMR, is now entering production. Given the timescale associated with HAMR development it seems important to consider the possibilities for future replacement. HAMR is limited by the phenomenon of 'backswitching' which, in the limited write fields available to the HAMR process, leads to a reduction of switching probability: a reduction which becomes more pronounced as the grain size continues to decrease. An interesting possibility for technology beyond HAMR is All-Optical Switching (AOS), which is a field free option thereby removing the need for an inductively generated head field. Since the AOS is driven by exchange, the effective fields involved are extremely large, the backswitching is dramatically reduced leading to more reliable switching. We review the underlying physics of the backswitching in terms of a 'quadrilemma' and show how this is overcome by AOS. We also outline recent processes designed to switch ferromagnets and the usage of combined AOS/spin torque to achieve deterministic rather than the toggle switching exhibited by ferrimagnets. The conclusion is that any materials design must ensure a sufficiently large effective field to overcome backswitching.
AB - After 20 years of development heat assisted magnetic recording, HAMR, is now entering production. Given the timescale associated with HAMR development it seems important to consider the possibilities for future replacement. HAMR is limited by the phenomenon of 'backswitching' which, in the limited write fields available to the HAMR process, leads to a reduction of switching probability: a reduction which becomes more pronounced as the grain size continues to decrease. An interesting possibility for technology beyond HAMR is All-Optical Switching (AOS), which is a field free option thereby removing the need for an inductively generated head field. Since the AOS is driven by exchange, the effective fields involved are extremely large, the backswitching is dramatically reduced leading to more reliable switching. We review the underlying physics of the backswitching in terms of a 'quadrilemma' and show how this is overcome by AOS. We also outline recent processes designed to switch ferromagnets and the usage of combined AOS/spin torque to achieve deterministic rather than the toggle switching exhibited by ferrimagnets. The conclusion is that any materials design must ensure a sufficiently large effective field to overcome backswitching.
KW - all-optical switching
KW - HAMR limitation
KW - recording quadrilemma
UR - http://www.scopus.com/inward/record.url?scp=85215368758&partnerID=8YFLogxK
U2 - 10.1109/TMAG.2025.3530769
DO - 10.1109/TMAG.2025.3530769
M3 - Article
AN - SCOPUS:85215368758
SN - 0018-9464
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
ER -