![Sam Ladak](https://profiles-cardiff.imgix.net/attachments/3767?w=200&h=200&auto=format&crop=faces&fit=crop&q=90")
Dr Sam Ladak
Reader
Condensed Matter and Photonics Group
School of Physics and Astronomy
- LadakS@cardiff.ac.uk
- +44 29208 70157
- Queen's Buildings - West Building Extension, Room WX/3.06, 5 The Parade, Newport Road, Cardiff, CF24 3AA
- Available for postgraduate supervision
Overview
In 2012, I was awarded a personal chancellors (SBP) fellowship within the School of Physics and Astronomy with the aim of establishing a research group within the emerging field of 3D nanomagnetism. Prior to this I was a research fellow at Imperial College where I researched artificial spin-ice materials.
Today, the focus of my work is upon 3D magnetic nanostructure fabrication, via two-photon lithogrpahy and subsequent characterisation using magnetic imaging and optical magnetometry.
Over the past several years I have secured > £2M of external funding from the EPSRC and Leverhulme Trust.
I routinely work with other academics from other leading universities (Exeter, Bristol, Southampton) as well as large international research labs (eg. IBM Zurich).
More details of my laboratory and research can be found at my website below:
Ladak Lab
My citation information can be found here
Publication
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)
Research
The focus of my work is upon 3D magnetic nanostructure fabrication and characterisation.
Over the past several years I have secured > £2M of external (EPSRC) funding as well as small grants from the Royal Society, Welsh Crucible and Cardiff.
I routinely work with other academics from other leading universities (Exeter, Bristol, Southampton) as well as large international research labs (eg. IBM Zurich).
More details of my laboratory and research can be found at my website below:
http://www.ladaklab.com
Teaching
I currently teach the third year course "Environmental Physics" and the fourth year course "Magnetism and Superconductivity". In addtion, I teach first year tutorial classes and supervise a number of third / fourth year undergraduate projects.
Biography
I completed my PhD from the University of Exeter in 2006. The project involved the fabrication and characterisation of magnetic tunnel junctions. After this I carried out a year in industry at Seagate technology, designing and prototyping magnetic read-heads.
In 2007 I decided to go back to academia and took up postdoctoral positions at the University of York and then Imperial College where I remained for four years.
Throughout my academic career my research has centred on magnetic materials but more recently has focussed on 3D nano-magnetic systems. I was awarded a chancellors fellowship and was employed as a permanent lecturer in physics at Cardiff University in November 2012. In 2018 I was promoted to senior lecturer and then to Reader in 2021
Honours and awards
I am a member of the Editorial Board for the Nature family journal Scientific Reports.
Professional memberships
Institute of Physics : Fellow
