School of Physics and Astronomy

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Dr Oscar Cespedes

Condensed Matter Group

Contact details

Room: 8.302
Tel: +44 (0)113 3431885
Email: o.cespedes @


Carbon nanomaterials
C60 magnetic tunnel junctions
Spin transport in graphene and carbon nanotubes
Raman spectroscopy

Research interests

My research interests cover a broad range of topics, including:

1.- Electron and spin dependent transport in carbon based materials, such as magnetic tunnel junctions with buckyballs(C60), and spintronics in graphene, carbon nanotubes and other organics.

2.- Magnetic field dependent transport in nanostructures, such as magnetic oxide nanoconstrictions (Fe3O4, NiOx, LSMO) and gas-stabilised break junctions.

3.- The electron/spin-phonon interaction in hybrid devices (probed by Raman, Brillouin light scattering and other techniques).

4.- Biomagnetism and novel mechanisms of interactions between RF/microwave magnetic fields and proteins.

5.- Exobiology and protein dynamics in conditions simulating those of other planets and/or outer space, including Raman microscopy at low temperatures (down to ~3 K) or under simulated microgravity using magnetic fields.

6.- The magnetic and optical properties of magnetic nanoparticles for device and biological applications.

Useful links

Research website
Group website


Kulmaczewski R, Cespedes O, Halcrow MA Gradual Thermal Spin-Crossover Mediated by a Reentrant Z' = 1→ Z' = 6 → Z' = 1 Phase Transition. Inorg Chem 56 3144-3148, 2017
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Fang Z, Mitra A, Westerman AL, Ali M, Ciccarelli C, Cespedes O, Hickey BJ, Ferguson AJ Thickness dependence study of current-driven ferromagnetic resonance in Y3Fe5O12/heavy metal bilayers Applied Physics Letters 110 -, 2017
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Talalaevskij A, Decker M, Stigloher J, Mitra A, Körner HS, Cespedes O, Back CH, Hickey BJ Magnetic properties of spin waves in thin yttrium iron garnet films Physical Review B - Condensed Matter and Materials Physics 95 -, 2017
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Halcrow MA, Kulmaczewski RL, Cespedes O Data to support study of Gradual Thermal Spin-Crossover Mediated by a Re-Entrant Z? = 1 to Z? = 6 to Z? = 1 Phase Transition., 2017

Kulak AN, Grimes R, Kim YY, Semsarilar M, Anduix-Canto C, Cespedes O, Armes SP, Meldrum FC Polymer-Directed Assembly of Single Crystal Zinc Oxide/Magnetite Nanocomposites under Atmospheric and Hydrothermal Conditions Chemistry of Materials 28 7528-7536, 2016
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Cepriá G, Córdova WR, Céspedes O, Sánchez-García L, Ferrer P, Gianolio D, Castillo JR Physical and chemical characterization of cerium(IV) oxide nanoparticles Analytical and Bioanalytical Chemistry 408 6589-6598, 2016
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Ye S, Benz F, Wheeler MC, Oram J, Baumberg JJ, Cespedes O, Christenson HK, Coletta PL, Jeuken LJC, Markham AF, Critchley K, Evans SD One-step fabrication of hollow-channel gold nanoflowers with excellent catalytic performance and large single-particle SERS activity Nanoscale 8 14932-14942, 2016
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Optimization of magnetocaloric properties of arc-melted and spark plasma-sintered LaFe11.6Si1.4 Applied Physics A: Materials Science and Processing 122 -, 2016
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Henrichs LF, Cespedes O, Bennett J, Landers J, Salamon S, Heuser C, Hansen T, Helbig T, Gutfleisch O, Lupascu DC, Wende H, Kleemann W, Bell AJ Multiferroic Clusters: A New Perspective for Relaxor-Type Room-Temperature Multiferroics ADVANCED FUNCTIONAL MATERIALS 26 2111-2121, 2016

Cook LJK, Kulmaczewski R, Cespedes O, Halcrow MA Different Spin-State Behaviors in Isostructural Solvates of a Molecular Iron(II) Complex Chemistry - A European Journal 22 1789-1799, 2016
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Al Ma'Mari F, Moorsom T, Teobaldi G, Deacon W, Prokscha T, Luetkens H, Lee S, Sterbinsky GE, Arena DA, MacLaren DA, Flokstra M, Ali M, Wheeler MC, Burnell G, Hickey BJ, Cespedes O Beating the Stoner criterion using molecular interfaces. Nature 524 69-73, 2015
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Kershaw Cook LJ, Thorp-Greenwood FL, Comyn TP, Cespedes O, Chastanet G, Halcrow MA Unexpected Spin-Crossover and a Low-Pressure Phase Change in an Iron(II)/Dipyrazolylpyridine Complex Exhibiting a High-Spin Jahn-Teller Distortion Inorganic Chemistry 54 6319-6330, 2015
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Popuri SR, Redpath D, Chan G, Smith RI, Cespedes O, Bos JWG Antisite-disorder, magnetic and thermoelectric properties of Mo-rich Sr<inf>2</inf>Fe<inf>1-y</inf>Mo<inf>1+y</inf>O<inf>6</inf> (0≤ y ≤ 0.2) double perovskites Dalton Transactions 44 10621-10627, 2015
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Cook LJK, Shepherd HJ, Comyn TP, Baldé C, Cespedes O, Chastanet G, Halcrow MA Decoupled spin crossover and structural phase transition in a molecular iron(II) complex Chemistry - A European Journal 21 4805-4816, 2015
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Santoro A, Kershaw Cook LJ, Kulmaczewski R, Barrett SA, Cespedes O, Halcrow MA Iron(II) complexes of tridentate indazolylpyridine ligands: Enhanced spin-crossover hysteresis and ligand-based fluorescence Inorganic Chemistry 54 682-693, 2015
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Chowdhury M, Oputu O, Kebede M, Cummings F, Cespedes O, Maelsand A, Fester V Rapid and large-scale synthesis of Co3O4octahedron particles with very high catalytic activity, good supercapacitance and unique magnetic properties RSC Advances 5 104991-105002, 2015
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Mari FAM, Moorsom T, Teobaldi G, Deacon W, Prokscha T, Luetkens H, Lee S, Sterbinsky GE, Arena DA, MacLaren DA, Flokstra M, Ali M, Wheeler MC, Burnell G, Hickey B, Cespedes O Beating the Stoner Criterion, 2015

Cespedes O, Wheeler M, Moorsom T, Viret M Unexpected magnetic properties of gas-stabilized platinum nanostructures in the tunneling regime Nano Letters 15 45-50, 2014
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Ma'Mari FA, Wheeler M, Kendric E, Burnell G, Hickey BJ, Moorsom T, Cespedes O Direct Measurement of spin polarization in ferromagnetic-C60 interfaces using point-contact andreev reflection IEEE Transactions on Magnetics 50 -, 2014
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Moorsom T, Wheeler M, Mohd Khan T, Al Ma'Mari F, Kinane C, Langridge S, Ciudad D, Bedoya-Pinto A, Hueso L, Teobaldi G, Lazarov VK, Gilks D, Burnell G, Hickey BJ, Cespedes O Spin-polarized electron transfer in ferromagnet/C60 interfaces Physical Review B - Condensed Matter and Materials Physics 90 -, 2014
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Kulmaczewski R, Shepherd HJ, Cespedes O, Halcrow MA A homologous series of [Fe(H₂Bpz₂)₂(L)] spin-crossover complexes with annelated bipyridyl co-ligands. Inorg Chem 53 9809-9817, 2014
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Venugopal A, Cespedes O, Russell SJ Controlling dielectric and magnetic properties of PVdF/Magnetite nanocomposite fibre webs. International Journal of Polymer Science 2014 -, 2014
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Chowdhury MR, Fester V, Kale G, Cespedes O Hydrothermal precipitation of beta-FeOOH nanostructure(s) in mixed solvent: study of their morphological and structural evolution JOURNAL OF NANOPARTICLE RESEARCH 16 -, 2014

Kulak AN, Semsarilar M, Kim YY, Ihli J, Fielding LA, Cespedes O, Armes SP, Meldrum FC One-pot synthesis of an inorganic heterostructure: Uniform occlusion of magnetite nanoparticles within calcite single crystals Chemical Science 5 738-743, 2014
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Kim YY, Schenk AS, Walsh D, Kulak AN, Cespedes O, Meldrum FC Bio-inspired formation of functional calcite/metal oxide nanoparticle composites. Nanoscale 6 852-859, 2014
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Moorsom T, Wheeler M, Taukeer Khan M, Al Ma'Mari F, Burnell G, Hickey BJ, Lazarov V, Gilks D, Cespedes O Effects of spin doping and spin injection in the luminescence and vibrational spectrum of C60 Applied Physics Letters 105 -, 2014
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Gilks D, Lari L, Naughton J, Cespedes O, Cai Z, Gerber A, Thompson SM, Ziemer K, Lazarov VK Origin of anomalous magnetite properties in crystallographic matched heterostructures: Fe3O4(111)/MgAl2O4(111) Journal of Physics Condensed Matter 25 -, 2013
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Zhang Y, Pilapong C, Guo Y, Ling Z, Cespedes O, Quirke P, Zhou DJ Sensitive, Simultaneous Quantitation of Two Unlabeled DNA Targets Using a Magnetic Nanoparticle-Enzyme Sandwich Assay Analytical Chemistry -, 2013
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Gilks D, Lari L, Cai Z, Cespedes O, Gerber A, Thompson S, Ziemer K, Lazarov VK Magnetism and magnetotransport in symmetry matched spinels: Fe3O4/MgAl2O4 Journal of Applied Physics 113 -, 2013
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Wheeler M, Hickey BJ, Cespedes O Enhanced exchange bias of spin valves fabricated on fullerene-based seed layers IEEE Transactions on Magnetics 48 3047-3050, 2012
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Aljabali AAA, Barclay JE, Cespedes O, Rashid A, Staniland SS, Lomonossoff GP, Evans DJ Charge Modified Cowpea Mosaic Virus Particles for Templated Mineralization ADVANCED FUNCTIONAL MATERIALS 21 4137-4142, 2011

Garcia J, Zhang Y, Taylor H, Cespedes O, Webb WE, Zhou DJ Multilayer enzyme-coupled magnetic nanoparticles as efficient, reusable biocatalysts and biosensors Nanoscale 3 3721-3730, 2011
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Céspedes O, Inomoto O, Kai S, Nibu Y, Yamaguchi T, Sakamoto N, Akune T, Inoue M, Kiss T, Ueno S Radio frequency magnetic field effects on molecular dynamics and iron uptake in cage proteins. Bioelectromagnetics 31 311-317, 2010
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Cespedes O, Inomoto O, Kai S, Ueno S Effects of Cationization and 6-Hydroxydopamine on the Reduced Iron Release Rates From Ferritin by Radio-Frequency Magnetic Fields, 2009

Céspedes O, Ueno S Effects of radio frequency magnetic fields on iron release from cage proteins. Bioelectromagnetics 30 336-342, 2009
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Cespedes O, Viret M Normal and reversed tunable magnetoresistance in a NiOx/p-doped silicon diode APPL PHYS LETT 94 -, 2009

Cespedes O, Luu A, Rhen FMF, Coey JMD Fabrication of Magnetic Force Microscopy Tips via Electrodeposition and Focused Ion Beam Milling, 2008

Cespedes O, Viret M, Coey JMD Magnetoresistance in NiOx nanoconstrictions controlled by magnetic fields and currents J APPL PHYS 103 -, 2008

Cespedes O, Watts SM, Coey JMD, Dorr K, Ziese M Magnetoresistance and electrical hysteresis in stable half-metallic La0.7Sr0.3MnO3 and Fe3O4 nanoconstrictions APPL PHYS LETT 87 -, 2005

Cespedes O, Clifford E, Coey JMD Spin polarization of Nb/Ni nanocontacts measured by Andreev reflection in planar thin-film geometry, 2005

Cespedes O, Clifford E, Coey JMD Magnetoresistance of magnetite point contacts and nanoconstrictions J APPL PHYS 97 -, 2005

Cespedes O, Rocha AR, Lioret S, Viret M, Dennis C, Gregg JF, van Dijken S, Sanvito S, Coey JMD I-V asymmetry and magnetoresistance in nickel nanoconstrictions, 2004

Cespedes O, Ferreira MS, Sanvito S, Kociak M, Coey JMD Contact induced magnetism in carbon nanotubes J PHYS-CONDENS MAT 16 L155-L161, 2004

Cespedes O, Jan G, Viret M, Bari M, Coey JMD Random telegraph noise in a nickel nanoconstriction J APPL PHYS 93 8433-8435, 2003

Jan G, Cespedes O, Fitzgerald C, Bari M, Coey JMD Noise in thin half-metallic oxide films Digests of the Intermag Conference -, 2002
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Raquet B, Broto JM, Viret A, Sondergard E, Cespedes O Electronic scattering and spin disorder in 3d-ferromagnets in the paraprocess regime, 2002

Raquet B, Viret M, Sondergard E, Cespedes O, Mamy R Electron-magnon scattering and magnetic resistivity in 3d ferromagnets PHYS REV B 66 -, 2002

Raquet B, Viret M, Broto JM, Sondergard E, Cespedes O, Mamy R Magnetic resistivity and electron-magnon scattering in 3d ferromagnets, 2002

Cespedes O, Bari MA, Dennis C, Versluijs JJ, Jan G, O'Sullivan J, Gregg JF, Coey JMD Fabrication and characterisation of Ni nanocontacts, 2002