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Dr Sam Ladak
Darllenydd
Grŵp Mater Cyddwysedig a Ffotoneg
- LadakS@caerdydd.ac.uk
- +44 29208 70157
- Adeiladau'r Frenhines - estyniad y Gorllewin, Ystafell WX/3.06, 5 The Parade, Heol Casnewydd, Caerdydd, CF24 3AA
- Ar gael fel goruchwyliwr ôl-raddedig
Trosolwyg
Yn 2012, dyfarnwyd cymrodoriaeth cangellorion personol (SBP) i mi yn yr Ysgol Ffiseg a Seryddiaeth gyda'r nod o sefydlu grŵp ymchwil ym maes nanomagneteg 3D sy'n dod i'r amlwg. Cyn hyn, roeddwn yn gymrawd ymchwil yng Ngholeg Imperial lle ymchwiliais i ddeunyddiau sbin-iâ artiffisial.
Heddiw, mae fy ngwaith yn canolbwyntio ar wneuthuriad nanostructure magnetig 3D, trwy lithogrpahy dau ffoton a chymeriad dilynol gan ddefnyddio delweddu magnetig a magnetometreg optegol.
Dros y blynyddoedd diwethaf rwyf wedi sicrhau > £2M o gyllid allanol gan yr EPSRC ac Ymddiriedolaeth Leverhulme.
Rwy'n gweithio'n rheolaidd gydag academyddion eraill o brifysgolion blaenllaw eraill (Caerwysg, Bryste, Southampton) yn ogystal â labordai ymchwil rhyngwladol mawr (ee. IBM Zurich).
Mae rhagor o fanylion am fy labordy a'm hymchwil i'w gweld ar fy ngwefan isod:
Ladak Lab
Gellir dod o hyd i'm gwybodaeth yma
Cyhoeddiad
2024
- Harding, E. et al. 2024. Imaging the magnetic nanowire cross-section and magnetic ordering within a suspended 3D artificial spin-ice. APL Materials 12, article number: 21116. (10.1063/5.0176907)
2023
- Saccone, M., Van den Berg, A., Harding, E., Singh, S., Giblin, S. R., Flicker, F. and Ladak, S. 2023. Exploring the phase diagram of 3D artificial spin-ice. Communications Physics 6(1), article number: 217. (10.1038/s42005-023-01338-2)
- van den Berg, A., Carouel, M., Hunt, M. and Ladak, S. 2023. Combining two-photon lithography with laser ablation of sacrificial layers: a route to isolated 3D magnetic nanostructures. Nano Research 16, pp. 1441-1447. (10.1007/s12274-022-4649-z)
2022
- Ladak, S., Fernandez-Pacheco, A. and Fischer, P. 2022. Science and technology of 3D magnetic nanostructures. APL Materials 10(12), article number: 120401. (10.1063/5.0136801)
- Askey, J., Hunt, M., Langbein, W. and Ladak, S. 2022. Asymmetric dual Bloch point domain walls in cylindrical magnetic nanowires. APL Materials 10(7), article number: 71105. (10.1063/5.0089291)
- Chumak, A. V. et al. 2022. Advances in magnetics roadmap on spin-wave computing. IEEE Transactions on Magnetics 58(6), article number: 800172. (10.1109/tmag.2022.3149664)
2021
- Barman, A. et al. 2021. The 2021 Magnonics Roadmap. Journal of Physics: Condensed Matter 33(41), article number: 413001. (10.1088/1361-648X/abec1a)
- Sahoo, S., May, A., van Den Berg, A., Mondal, A. K., Ladak, S. and Barman, A. 2021. Observation of coherent spin waves in a three-dimensional artificial spin ice structure. Nano Letters 21(11), pp. 4629-4635. (10.1021/acs.nanolett.1c00650)
- May, A., Saccone, M., Van Den Berg, A., Askey, J., Hunt, M. and Ladak, S. 2021. Magnetic charge propagation upon a 3D artificial spin-ice. Nature Communications 12, article number: 3217. (10.1038/s41467-021-23480-7)
2020
- Askey, J., Hunt, M. O., Langbein, W. and Ladak, S. 2020. Use of two-photon lithography with a negative resist and processing to realise cylindrical magnetic nanowires. Nanomaterials 10(3), article number: 429. (10.3390/nano10030429)
- Hunt, M. et al. 2020. Harnessing multi-photon absorption to produce three-dimensional magnetic structures at the nanoscale. Materials 13(3), article number: 761. (10.3390/ma13030761)
2019
- May, A., Hunt, M., Van Den Berg, A., Hejazi, A. and Ladak, S. 2019. Realisation of a frustrated 3D magnetic nanowire lattice. Communications Physics 2, article number: 13. (10.1038/s42005-018-0104-6)
2018
- Sahoo, S., Mondal, S., Williams, G., May, A., Ladak, S. and Barman, A. 2018. Ultrafast magnetization dynamics in a nanoscale three- dimensional cobalt tetrapod structure. Nanoscale 10(21), pp. 9981-9986. (10.1039/C7NR07843A)
- Thomas, R., Li, J., Ladak, S., Barrow, D. and Smowton, P. 2018. In-situ fabricated 3D micro-lenses for photonic integrated circuits. Optics Express 26(10), pp. 13436-13442. (10.1364/OE.26.013436)
- Williams, G. et al. 2018. Two-photon lithography for 3D magnetic nanostructure fabrication. Nano Research 11(2), pp. 845-854. (10.1007/s12274-017-1694-0)
2017
- Putman, N. F., Naisbett-Jones, L. C., Stephenson, J. F., Ladak, S. and Young, K. F. 2017. Response to Durif et al.. Current Biology 27(18), pp. R1000-R1001. (10.1016/j.cub.2017.08.046)
- Naisbett-Jones, L. C., Putman, N. F., Stephenson, J. F., Ladak, S. and Young, K. A. 2017. A magnetic map leads juvenile European eels to the Gulf Stream. Current Biology 27(8), pp. 1236-1240. (10.1016/j.cub.2017.03.015)
2015
- Walton, S. K. et al. 2015. Limitations in artificial spin ice path selectivity: the challenges beyond topological control. New Journal of Physics 17, article number: 13054. (10.1088/1367-2630/17/1/013054)
2013
- Ladak, S. et al. 2013. Observation of wrinkle induced potential drops in biased chemically derived graphene thin film networks. Carbon 64, pp. 35-44.
- Zeissler, K., Walton, S. K., Ladak, S., Read, D., Tyliszczak, T., Cohen, L. F. and Branford, W. R. 2013. The non-random walk of chiral magnetic charge carriers in artificial spin ice. Scientific Reports 3, article number: 1252. (10.1038/srep01252)
2012
- Ladak, S., Walton, S. K., Zeissler, K., Tyliszczak, T., Read, D., Branford, W. R. and Cohen, L. F. 2012. Disorder-independent control of magnetic monopole defect population in artificial spin-ice honeycombs. New Journal of Physics 14(4), article number: 45010. (10.1088/1367-2630/14/4/045010)
- Branford, W. R., Ladak, S., Read, D., Zeissler, K. and Cohen, L. F. 2012. Emerging chirality in artificial spin ice. Science 335(6076), pp. 1597-1600. (10.1126/science.1211379)
2011
- Ladak, S., Read, D., Branford, W. R. and Cohen, L. F. 2011. Direct observation and control of magnetic monopole defects in an artificial spin-ice material. New Journal of Physics 13, article number: 63032. (10.1088/1367-2630/13/6/063032)
- Gilbertson, A. M. et al. 2011. Sub-100-nm negative bend resistance ballistic sensors for high spatial resolution magnetic field detection. Applied Physics Letters 98(6), article number: 62106. (10.1063/1.3554427)
- Ladak, S., Read, D., Tyliszczak, T., Branford, W. R. and Cohen, L. F. 2011. Monopole defects and magnetic Coulomb blockade. New Journal of Physics 13(2), article number: 23023. (10.1088/1367-2630/13/2/023023)
2010
- Davidson, A. J., Brown, C. V., Mottram, N. J., Ladak, S. and Evans, C. R. 2010. Defect trajectories and domain-wall loop dynamics during two-frequency switching in a bistable azimuthal nematic device. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics 81(5), article number: 51712. (10.1103/PhysRevE.81.051712)
- Ladak, S., Read, D., Perkins, G. K., Cohen, L. F. and Branford, W. R. 2010. Direct observation of magnetic monopole defects in an artificial spin-ice system [Letter]. Nature Physics 6(5), pp. 359-363. (10.1038/nphys1628)
2009
- Hirohata, A., Ladak, S., Aley, N. P. and Hix, G. B. 2009. Si segregation in polycrystalline Co2MnSi films with grain-size control. Applied Physics Letters 95(25), article number: 252506. (10.1063/1.3276073)
- Ladak, S. et al. 2009. Magnetic and structural properties of laminated Co65Fe35 films. Journal of Magnetism and Magnetic Materials 321(8), pp. 996-1000. (10.1016/j.jmmm.2008.03.019)
- Ladak, S., Davidson, A., Brown, C. V. and Mottram, N. J. 2009. Sidewall control of static azimuthal bistable nematic alignment states. Journal of Physics D: Applied Physics 42(8), article number: 85114. (10.1088/0022-3727/42/8/085114)
2008
- Ladak, S., Fernandez-Outon, L. E. and O'Grady, K. 2008. Influence of seed layer on magnetic properties of laminated Co65Fe35 films. Journal of Applied Physics 103(7), article number: 07B514. (10.1063/1.2832436)
2006
- Telling, N. D., Van der Laan, G., Ladak, S., Hicken, R. J. and Arenholz, E. 2006. Evidence of a barrier oxidation dependence on the interfacial magnetism in Co/alumina based magnetic tunnel junctions. Journal of Applied Physics 99(8), pp. 0. (10.1063/1.2171002)
2005
- Ladak, S. and Hicken, R. J. 2005. Evidence for hot electron magnetocurrent in a double barrier tunnel junction device. Applied Physics Letters 87(23), article number: 232504. (10.1063/1.2140480)
- Ladak, S. and Hicken, R. J. 2005. Origin of large magnetocurrent in three-terminal double-barrier magnetic tunnel junctions. Journal of Applied Physics 97(10), article number: 104512. (10.1063/1.1905790)
- Keatley, P. S., Kruglyak, V. V., Barman, A., Ladak, S., Hicken, R. J., Scott, J. and Rahman, M. 2005. Use of microscale coplanar striplines with indium tin oxide windows in optical ferromagnetic resonance measurements. Journal of Applied Physics 97(10), article number: 10R304. (10.1063/1.1849071)
2004
- Telling, N. D., van der Laan, G., Ladak, S. and Hicken, R. J. 2004. Spin polarization and barrier-oxidation effects at the Co/alumina interface in magnetic tunnel junctions. Applied Physics Letters 85(17), pp. 3803-3805. (10.1063/1.1812383)
2003
- Hicken, R. J., Barman, A., Kruglyak, V. V. and Ladak, S. 2003. Optical ferromagnetic resonance studies of thin film magnetic structures. Journal of Physics D: Applied Physics 36(18), pp. 2183-2192. (10.1088/0022-3727/36/18/002)
Articles
- Harding, E. et al. 2024. Imaging the magnetic nanowire cross-section and magnetic ordering within a suspended 3D artificial spin-ice. APL Materials 12, article number: 21116. (10.1063/5.0176907)
- Saccone, M., Van den Berg, A., Harding, E., Singh, S., Giblin, S. R., Flicker, F. and Ladak, S. 2023. Exploring the phase diagram of 3D artificial spin-ice. Communications Physics 6(1), article number: 217. (10.1038/s42005-023-01338-2)
- van den Berg, A., Carouel, M., Hunt, M. and Ladak, S. 2023. Combining two-photon lithography with laser ablation of sacrificial layers: a route to isolated 3D magnetic nanostructures. Nano Research 16, pp. 1441-1447. (10.1007/s12274-022-4649-z)
- Ladak, S., Fernandez-Pacheco, A. and Fischer, P. 2022. Science and technology of 3D magnetic nanostructures. APL Materials 10(12), article number: 120401. (10.1063/5.0136801)
- Askey, J., Hunt, M., Langbein, W. and Ladak, S. 2022. Asymmetric dual Bloch point domain walls in cylindrical magnetic nanowires. APL Materials 10(7), article number: 71105. (10.1063/5.0089291)
- Chumak, A. V. et al. 2022. Advances in magnetics roadmap on spin-wave computing. IEEE Transactions on Magnetics 58(6), article number: 800172. (10.1109/tmag.2022.3149664)
- Barman, A. et al. 2021. The 2021 Magnonics Roadmap. Journal of Physics: Condensed Matter 33(41), article number: 413001. (10.1088/1361-648X/abec1a)
- Sahoo, S., May, A., van Den Berg, A., Mondal, A. K., Ladak, S. and Barman, A. 2021. Observation of coherent spin waves in a three-dimensional artificial spin ice structure. Nano Letters 21(11), pp. 4629-4635. (10.1021/acs.nanolett.1c00650)
- May, A., Saccone, M., Van Den Berg, A., Askey, J., Hunt, M. and Ladak, S. 2021. Magnetic charge propagation upon a 3D artificial spin-ice. Nature Communications 12, article number: 3217. (10.1038/s41467-021-23480-7)
- Askey, J., Hunt, M. O., Langbein, W. and Ladak, S. 2020. Use of two-photon lithography with a negative resist and processing to realise cylindrical magnetic nanowires. Nanomaterials 10(3), article number: 429. (10.3390/nano10030429)
- Hunt, M. et al. 2020. Harnessing multi-photon absorption to produce three-dimensional magnetic structures at the nanoscale. Materials 13(3), article number: 761. (10.3390/ma13030761)
- May, A., Hunt, M., Van Den Berg, A., Hejazi, A. and Ladak, S. 2019. Realisation of a frustrated 3D magnetic nanowire lattice. Communications Physics 2, article number: 13. (10.1038/s42005-018-0104-6)
- Sahoo, S., Mondal, S., Williams, G., May, A., Ladak, S. and Barman, A. 2018. Ultrafast magnetization dynamics in a nanoscale three- dimensional cobalt tetrapod structure. Nanoscale 10(21), pp. 9981-9986. (10.1039/C7NR07843A)
- Thomas, R., Li, J., Ladak, S., Barrow, D. and Smowton, P. 2018. In-situ fabricated 3D micro-lenses for photonic integrated circuits. Optics Express 26(10), pp. 13436-13442. (10.1364/OE.26.013436)
- Williams, G. et al. 2018. Two-photon lithography for 3D magnetic nanostructure fabrication. Nano Research 11(2), pp. 845-854. (10.1007/s12274-017-1694-0)
- Putman, N. F., Naisbett-Jones, L. C., Stephenson, J. F., Ladak, S. and Young, K. F. 2017. Response to Durif et al.. Current Biology 27(18), pp. R1000-R1001. (10.1016/j.cub.2017.08.046)
- Naisbett-Jones, L. C., Putman, N. F., Stephenson, J. F., Ladak, S. and Young, K. A. 2017. A magnetic map leads juvenile European eels to the Gulf Stream. Current Biology 27(8), pp. 1236-1240. (10.1016/j.cub.2017.03.015)
- Walton, S. K. et al. 2015. Limitations in artificial spin ice path selectivity: the challenges beyond topological control. New Journal of Physics 17, article number: 13054. (10.1088/1367-2630/17/1/013054)
- Ladak, S. et al. 2013. Observation of wrinkle induced potential drops in biased chemically derived graphene thin film networks. Carbon 64, pp. 35-44.
- Zeissler, K., Walton, S. K., Ladak, S., Read, D., Tyliszczak, T., Cohen, L. F. and Branford, W. R. 2013. The non-random walk of chiral magnetic charge carriers in artificial spin ice. Scientific Reports 3, article number: 1252. (10.1038/srep01252)
- Ladak, S., Walton, S. K., Zeissler, K., Tyliszczak, T., Read, D., Branford, W. R. and Cohen, L. F. 2012. Disorder-independent control of magnetic monopole defect population in artificial spin-ice honeycombs. New Journal of Physics 14(4), article number: 45010. (10.1088/1367-2630/14/4/045010)
- Branford, W. R., Ladak, S., Read, D., Zeissler, K. and Cohen, L. F. 2012. Emerging chirality in artificial spin ice. Science 335(6076), pp. 1597-1600. (10.1126/science.1211379)
- Ladak, S., Read, D., Branford, W. R. and Cohen, L. F. 2011. Direct observation and control of magnetic monopole defects in an artificial spin-ice material. New Journal of Physics 13, article number: 63032. (10.1088/1367-2630/13/6/063032)
- Gilbertson, A. M. et al. 2011. Sub-100-nm negative bend resistance ballistic sensors for high spatial resolution magnetic field detection. Applied Physics Letters 98(6), article number: 62106. (10.1063/1.3554427)
- Ladak, S., Read, D., Tyliszczak, T., Branford, W. R. and Cohen, L. F. 2011. Monopole defects and magnetic Coulomb blockade. New Journal of Physics 13(2), article number: 23023. (10.1088/1367-2630/13/2/023023)
- Davidson, A. J., Brown, C. V., Mottram, N. J., Ladak, S. and Evans, C. R. 2010. Defect trajectories and domain-wall loop dynamics during two-frequency switching in a bistable azimuthal nematic device. Physical Review E: Statistical, Nonlinear, and Soft Matter Physics 81(5), article number: 51712. (10.1103/PhysRevE.81.051712)
- Ladak, S., Read, D., Perkins, G. K., Cohen, L. F. and Branford, W. R. 2010. Direct observation of magnetic monopole defects in an artificial spin-ice system [Letter]. Nature Physics 6(5), pp. 359-363. (10.1038/nphys1628)
- Hirohata, A., Ladak, S., Aley, N. P. and Hix, G. B. 2009. Si segregation in polycrystalline Co2MnSi films with grain-size control. Applied Physics Letters 95(25), article number: 252506. (10.1063/1.3276073)
- Ladak, S. et al. 2009. Magnetic and structural properties of laminated Co65Fe35 films. Journal of Magnetism and Magnetic Materials 321(8), pp. 996-1000. (10.1016/j.jmmm.2008.03.019)
- Ladak, S., Davidson, A., Brown, C. V. and Mottram, N. J. 2009. Sidewall control of static azimuthal bistable nematic alignment states. Journal of Physics D: Applied Physics 42(8), article number: 85114. (10.1088/0022-3727/42/8/085114)
- Ladak, S., Fernandez-Outon, L. E. and O'Grady, K. 2008. Influence of seed layer on magnetic properties of laminated Co65Fe35 films. Journal of Applied Physics 103(7), article number: 07B514. (10.1063/1.2832436)
- Telling, N. D., Van der Laan, G., Ladak, S., Hicken, R. J. and Arenholz, E. 2006. Evidence of a barrier oxidation dependence on the interfacial magnetism in Co/alumina based magnetic tunnel junctions. Journal of Applied Physics 99(8), pp. 0. (10.1063/1.2171002)
- Ladak, S. and Hicken, R. J. 2005. Evidence for hot electron magnetocurrent in a double barrier tunnel junction device. Applied Physics Letters 87(23), article number: 232504. (10.1063/1.2140480)
- Ladak, S. and Hicken, R. J. 2005. Origin of large magnetocurrent in three-terminal double-barrier magnetic tunnel junctions. Journal of Applied Physics 97(10), article number: 104512. (10.1063/1.1905790)
- Keatley, P. S., Kruglyak, V. V., Barman, A., Ladak, S., Hicken, R. J., Scott, J. and Rahman, M. 2005. Use of microscale coplanar striplines with indium tin oxide windows in optical ferromagnetic resonance measurements. Journal of Applied Physics 97(10), article number: 10R304. (10.1063/1.1849071)
- Telling, N. D., van der Laan, G., Ladak, S. and Hicken, R. J. 2004. Spin polarization and barrier-oxidation effects at the Co/alumina interface in magnetic tunnel junctions. Applied Physics Letters 85(17), pp. 3803-3805. (10.1063/1.1812383)
- Hicken, R. J., Barman, A., Kruglyak, V. V. and Ladak, S. 2003. Optical ferromagnetic resonance studies of thin film magnetic structures. Journal of Physics D: Applied Physics 36(18), pp. 2183-2192. (10.1088/0022-3727/36/18/002)
Ymchwil
Mae fy ngwaith yn canolbwyntio ar saernïo a nodweddu nanostrwythur magnetig 3D.
Dros y blynyddoedd diwethaf rwyf wedi sicrhau > £2M o gyllid allanol (EPSRC) yn ogystal â grantiau bach gan y Gymdeithas Frenhinol, Crucible Cymru a Chaerdydd.
Rwy'n gweithio'n rheolaidd gydag academyddion eraill o brifysgolion blaenllaw eraill (Caerwysg, Bryste, Southampton) yn ogystal â labordai ymchwil rhyngwladol mawr (ee. IBM Zurich).
Mae rhagor o fanylion am fy labordy a'm hymchwil i'w gweld ar fy ngwefan isod:
http://www.ladaklab.com
Addysgu
Ar hyn o bryd rwy'n dysgu'r cwrs trydedd flwyddyn "Ffiseg Amgylcheddol" a'r cwrs bedwaredd flwyddyn "Magnetism and Superconductivity". Yn ychwanegol, rwy'n addysgu dosbarthiadau tiwtorial blwyddyn gyntaf ac yn goruchwylio nifer o brosiectau israddedig y drydedd flwyddyn / pedwaredd flwyddyn.
Bywgraffiad
Cwblheais fy PhD o Brifysgol Caerwysg yn 2006. Roedd y prosiect yn cynnwys ffugio a nodweddu cyffyrdd twnnel magnetig. Ar ôl hyn, cynhaliais flwyddyn mewn diwydiant ym maes technoleg Seagate, dylunio a phrototeipio pennau darllen magnetig.
Yn 2007 penderfynais fynd yn ôl i'r byd academaidd a chymryd swyddi ôl-ddoethurol ym Mhrifysgol Efrog ac yna Coleg Imperial lle arhosais am bedair blynedd.
Trwy gydol fy ngyrfa academaidd mae fy ymchwil wedi canolbwyntio ar ddeunyddiau magnetig ond yn fwy diweddar mae wedi canolbwyntio ar systemau nano-magnetig 3D. Dyfarnwyd cymrodoriaeth canghellor i mi a chefais fy nghyflogi fel darlithydd parhaol mewn ffiseg ym Mhrifysgol Caerdydd ym mis Tachwedd 2012. Yn 2018 cefais fy nyrchafu yn uwch ddarlithydd ac yna i Ddarllenydd yn 2021
Anrhydeddau a dyfarniadau
Rwy'n aelod o'r Bwrdd Golygyddol ar gyfer cyfnodolyn teulu Nature Scientific Reports.
Aelodaethau proffesiynol
Sefydliad Ffiseg : Cymrawd
