Professor Kevin O'Grady, BSc, PhD (Wales), FInstP,
SMIEEE, Past President IEEE Magnetics Society

Contact details

Mail:
 Department of Physics
University of York
Heslington
York
YO10 5DD
U.K.
Tel:
 +44 (0)1904 432289
Fax:
 +44 (0)1904 432214
E-mail:
 kog1@york.ac.uk
Room:
 P/F006

Research Group

  • Mr Nick Aley
  • Mr Tom Deakin
  • Dr Luis Fernandez-Outon
  • Ms Barbara Kaeswurm
  • Dr Gonzalo Vallejo-Fernandez

Experimental Facilities

The group maintains an extensive suite of magnetometers which provides the most comprehensive measurement capability for magnetic properties in Europe. Specific facilities are:

  • ADE Model 10 vibrating sample magnetometer
  • Lakeshore Model 4500 vibrating sample magnetometer
  • Princeton Measurements Corporation Model 2900 alternating gradient force magnetometer
  • 2 further vibrating sample magnetometers including specialist low field facility
  • 50 Hertz 7kOe B-H hysteresis loop tracer
  • 2 AC susceptometers
  • High stability MOKE system
  • Focused MOKE system
  • Secondary standard Bell Gauss Hall probe
  • Plasma Quest Ltd controlled sputter deposition system

Recent Publications

S LADAK, L E FERNANDEZ-OUTON AND K O'GRADY
Influence of seed layer on magnetic properties of laminated Co65Fe35 films
J. Appl. Phys. 103 (2008) 07B514 (3 pages)

L E FERNANDEZ-OUTON, G VALLEJO-FERNANDEZ AND K O'GRADY
Interfacial Spin Effects on Hex in Metallic Polycrystalline Exchange Biased Systems
J. Appl. Phys. 103 (2008) 07C106 (3 pages)

G VALLEJO-FERNANDEZ, L E FERNANDEZ-OUTON AND K O’GRADY
Thermal Activation of Bulk and Interfacial Order in Exchange Biased Systems
J. Appl. Phys.103 (2008) 07C101 (3 pages)

T DEAKIN AND K O’GRADY
Magnetic Characterization of Exchange-Coupled Composite Media
J. Appl. Phys. 103 (2008) 07F503 (3 pages)

B CRAIG, R LAMBERTON, A JOHNSTON, U NOWAK, R W CHANTRELL AND K O'GRADY
A Model of the Temperature Dependence of Exchange Bias in Coupled Ferromagnetic/Antiferromagnetic Bilayers
J. Appl. Phys. 103 (2008) 07C102 (3 pages)

G VALLEJO-FERNANDEZ, L E FERNANDEZ-OUTON AND K O’GRADY
Measurement of the anisotropy constant of antiferromagnets in metallic polycrystalline exchange biased systems
Appl. Phys. Lett. 91 (2007) p. 212503 (3 pages)

G VALLEJO-FERNANDEZ, T DIMOPOULOS, M RUEHRIG AND K O'GRADY
Annealing effect on thermal stability and microstructure in IrMn/Co60Fe20B20 bilayers
J. Magn. Magn. Mater. 310 E769-E771 (2007)

SJF CHADWICK, MA GONZALEZ-FERNANDEZ AND K O'GRADY
Competing interaction effects in recording media
J. Magn. Magn. Mater. 316 203-205 (2007)

A VIRDEN, S WELLS AND K O'GRADY
Physical and magnetic properties of highly anisotropic cobalt ferrite particles
J. Magn. Magn. Mater. 316 E768-E771 (2007)

D CHOO, RW CHANTRELL, R LAMBERTON, A JOHNSTON AND K O'GRADY
A model of the magnetic properties of coupled ferromagnetic/antiferromagnetic bilayers
J. Appl. Phys. 101 09E521 (2007) (3 pages)

LE FERNANDEZ-OUTON, G VALLEJO-FERNANDEZ, S MANZOOR AND K O'GRADY
Thermal instability in exchange biased materials
J. Optoelectron. Adv. Mater. 9 1127-1132 (2007)

JD DUTSON, C HUERRICH, G VALLEJO-FERNANDEZ, LE FERNANDEZ-OUTON, G YI, S MAO, RW CHANTRELL AND K O'GRADY
Bulk and interfacial effects in exchange bias systems
J. Phys. D-Appl. Phys. 40 1293-1299 (2007) (7 pages)

JD DUTSON, M HASHIMOTO, Y INABA, SJ GREAVES, H MURAOKA AND K O'GRADY
Magnetic and recording properties of (CoCrPt)(1-x)(SiO2)(x) media
IEEE Trans. Magn. 43 814-818 (2007)

G VALLEJO-FERNANDEZ, M VOPSAROIU, LE FERNANDEZ-OUTON AND K O'GRADY
The role of interfaces in CoFe/IrMn exchange biased systems
IEEE Trans. Magn. 42 3008-3010 (2006)

BA JONES, JD DUTSON, K O'GRADY, BJ HICKEY, DR LI, N POUDYAL AND JP LIU
Magnetic properties of FePt nanoparticles annealed with NaCl
IEEE Trans. Magn. 42 3066-3068 (2006)

JD DUTSON, D LITVINOV, MRJ GIBBS, Y INABA, H MURAOKA AND K O'GRADY
Magnetisation reversal in media with perpendicular anisotropy
J. Magn. Magn. Mater. 304 51-54 (2006)

AG ROCA, MP MORALES, K O'GRADY AND CJ SERNA
Structural and magnetic properties of uniform magnetite nanoparticles prepared by high temperature decomposition of organic precursors
Nanotechnology 17 2783-2788 (2006)

LE FERNANDEZ-OUTON, G VALLEJO-FERNANDEZ, S MANZOOR AND K O'GRADY
Thermal instabilities in exchange biased materials
J. Magn. Magn. Mater. 303 296-301 (2006)

KC SCHUERMANN, JD DUTSON, SZ WU, SD HARKNESS, B VALCU, HJ RICHTER, RW CHANTRELL AND K O'GRADY
Exchange-coupling effects in perpendicular composite materials
J. Appl. Phys. 99 08Q904 (2006) (3 pages)

AE VIRDEN AND K O'GRADY
The temperature dependence of magnetization in ferrofluids
J. Appl. Phys. 99 08S106 (2006) (3 pages)

M BLANCO-MANTECON AND K O'GRADY
Interaction and size effects in magnetic nanoparticles
J. Magn. Magn. Mater. 296 124-133 (2006)

M. VOPSAROIU, M. J. THWAITES, G. V. FERNANDEZ, S. LEPADATU, AND K. O'GRADY.
Grain size effects in metallic thin films prepared using a new sputtering technology.
J. Optoelectronics Advanced Materials 7, 2713-2720 (2005).

Y. INABA, T. SHIMATSU, H. MURAOKA, J. D. DUTSON, AND K. O'GRADY.
Activation volumes in CoPtCr-SiO2 perpendicular recording media.
IEEE Trans. On Magnetics 41, 3130-3132 (2005).

M. VOPSAROIU, K. O'GRADY, M. T. GEORGIEVA, P. J. GRUNDY, AND M. J. THWAITES.
Growth rate effects in soft CoFe films.
IEEE Trans. On Magnetics 41, 3253-3255 (2005).

B. A. JONES AND K. O'GRADY.
Magnetically induced self-organization.
J. Applied Phys. 97, 10J312 (2005) (3 pages)

S. MANZOOR, M. VOPSAROIU, G. VALLEJO-FERNANDEZ, AND K. O'GRADY.
Grain-size effects in exchange-biased FeMn/NiFe bilayers.
J. Applied Phys. 97, 10K118 (2005) (3 pages)

M. VOPSAROIU, K. O'GRADY, and others (7).
Preparation of high moment CoFe films with controlled grain size and coercivity.
J. Applied Phys. 97, 10N303 (2005) (3 pages)

M. A. GONZALEZ-FERNANDEZ, C. BUNCE, K. O'GRADY, and others (7).
Texture and viscosity effects in particulate recording media.
J. Applied Phys. 97, 10P702 (2005) (3 pages)

B. A. JONES, J. A. SEARLE, AND K. O'GRADY.
Magnetic measurements of self-organisation.
J. Magnetism Magnetic Materials 290, 131-133 (2005).

S. J. F. CHADWICK, J. J. BLACKWELL, J. D. DUTSON, AND K. O'GRADY.
Magnetic viscosity in advanced metal particle pigments.
J. Magnetism Magnetic Materials 290, 134-137 (2005).

M. A. GONZALEZ-FERNANDEZ, C. BUNCE, K. O'GRADY, and others (7).
Texture effects in particulate media.
J. Magnetism Magnetic Materials 290, 498-501 (2005).

L. E. FERNANDEZ-OUTON AND K. O'GRADY.
Angular dependence of coercivity and exchange bias in IrMn/CoFe bilayers.
J. Magnetism Magnetic Materials 290, 536-539 (2005).

A. E. VIRDEN AND K. O'GRADY.
Structure and magnetic properties of NiZn ferrite nanoparticles.
J. Magnetism Magnetic Materials 290, 868-870 (2005).

M. VOPSAROIU, G. V. FERNANDEZ, M. J. THWAITES, J. ANGUITA, P. J. GRUNDY, AND K. O'GRADY.
Deposition of polycrystalline thin films with controlled grain size.
J. Phys. D-Applied Physics 38, 490-496 (2005).

M. VOPSAROIU, M. J. THWAITES, S. RAND, P. J. GRUNDY, AND K. O'GRADY.
Novel sputtering-technology for grain-size control.
IEEE Trans. On Magnetics 40, 2443-2445 (2004).

J. D. DUTSON, J. WU, K. O'GRADY, N. C. WOOLSEY, Y. KUBOTA, AND C. L. PLATT.
Time dependence in perpendicular media with a soft underlayer.
IEEE Trans. On Magnetics 40, 2504-2506 (2004).

L. E. FERNANDEZ-OUTON, K. O'GRADY, AND M. J. CAREY.
Thermal phenomena in IrMn exchange biased systems.
J. Applied Phys. 95, 6852-6854 (2004).

M. P. MORALES, O. BOMATI-MIGUEL, R. P. DEALEJO, J. RUIZ-CABELLO, S. VEINTEMILLAS-VERDAGUER, AND K. O'GRADY.
Contrast agents for MRI based on iron oxide nanoparticles prepared by laser pyrolysis.
J. Magnetism Magnetic Materials 266, 102-109 (2003).

J. J. BLACKWELL, K. O'GRADY, N. K. NELSON, AND M. P. SHARROCK.
The characterisation of magnetic pigment dispersions using pulsed magnetic fields.
J. Magnetism Magnetic Materials 266, 119-130 (2003).

J. D. DUTSON, K. O'GRADY, B. LU, Y. KUBOTA, AND C. L. PLATT.
Determination of activation volumes of reversal in perpendicular media.
IEEE Trans. On Magnetics 39, 2344-2346 (2003).

K. O'GRADY.
Biomedical applications of magnetic nanoparticles.
J. Phys. D-Applied Physics 36, Editorial (2003).

C. LODDER, R. INDECK, J. CHAPMAN, K. O'GRADY, J. DEBOECK, AND D. WELLER.
Selected papers from the 2002 International Magnetics Conference (Intermag 2002) - RAI Conference Center, Amsterdam, The Netherlands, April 28-May 2 (2002 - Foreword.
IEEE Trans. On Magnetics 38, 1858-1858 (2002).

J. WU, J. DUTSON, AND K. O'GRADY.
Magnetization reversal in AFC media.
IEEE Trans. On Magnetics 38, 1943-1945 (2002).

C. LODDER, J. CHAPMAN, J. DEBOECK, R. INDECK, K. O'GRADY, AND D. WELLER.
SELECTED PAPERS FROM THE 2002 INTERNATIONAL MAGNETICS CONFERENCE (INTERMAG 2002) RAI conference center, Amsterdam, the Netherlands, April 28-May 2 (2002 - Foreword.
IEEE Trans. On Magnetics 38, 1858-1858 (2002).

K. O'GRADY, L. HOLLOWAY, AND W. J. ANTEL.
Measurement of the energy barrier distribution in the antiferromagnetic layer of exchange-biased materials.
IEEE Trans. On Magnetics 38, 2741-2743 (2002).

Y. G. WANG, A. K. PETFORD-LONG, H. LAIDLER, K. O'GRADY, AND M. T. KIEF.
Thermally activated reversal in exchange-coupled structures.
IEEE Trans. On Magnetics 38, 2773-2775 (2002).

M. EL-HILO, K. O'GRADY, AND R. W. CHANTRELL.
Fluctuation fields and reversal mechanisms in granular magnetic systems.
J. Magnetism Magnetic Materials 248, 360-373 (2002).

G. N. PHILLIPS, K. O'GRADY, AND M. EL-HILO.
An investigation of time-dependent domain wall pinning effects in Tb/Fe multilayer thin films.
J. Magnetism Magnetic Materials 248, 418-422 (2002).

L. C. VARANDA, K. O'GRADY, and others (8).
Structural and magnetic transformation of monodispersed iron oxide particles in a reducing atmosphere.
J. Applied Phys. 92, 2079-2085 (2002).

T. HUGHES, W. J. ANTEL, H. LAIDLER, K. O'GRADY, AND M. T. KIEF.
Thermally activated reversal of the antiferromagnet in exchange biased IrMn/CoFe bilayers.
J. Magnetism Magnetic Materials 242, 1070-1072 (2002).

Y. G. WANG, A. K. PETFORD-LONG, T. HUGHES, H. LAIDLER, K. O'GRADY, AND M. T. KIEF.
Magnetisation reversal of the ferromagnetic layer in IrMn/CoFe bilayer films.
J. Magnetism Magnetic Materials 242, 1073-1076 (2002).

J. J. BLACKWELL, M. P. MORALES, K. O'GRADY, J. M. GONZALEZ, F. CEBOLLADA, AND M. ALONSO-SANUDO.
Interactions and hysteresis behaviour of Fe/SiO2 nanocomposites.
J. Magnetism Magnetic Materials 242, 1103-1105 (2002).

J. WU, K. O'GRADY, and others (8).
Magnetic characterization of perpendicular recording media.
IEEE Trans. On Magnetics 38, 1682-1686 (2002).

J. J. BLACKWELL, K. O'GRADY, C. VERDES, AND R. W. CHANTRELL.
Cluster demagnetizing effects in particulate dispersions.
J. Applied Phys. 91, 8748-8750 (2002).

W. J. ANTEL, H. LAIDLER, K. O'GRADY, C. VERDES, AND R. W. CHANTRELL.
Determination of activation volumes in thin film media.
J. Applied Phys. 91, 7080-7082 (2002).

H. LAIDLER, L. HOLLOWAY, AND K. O'GRADY.
Crystallographic defects in CoCrPt thin film media, effect on interactions and magnetic viscosity.
J. Phys. D-Applied Physics 35, 512-519 (2002).

A. C. C. YU, A. K. PETFORD-LONG, K. O'GRADY, AND T. MIYAZAKI.
Effect of Ti seed layer on the magnetization reversal process of Co/NiFe/Al-oxide/NiFe junction films.
J. Applied Phys. 91, 5234-5239 (2002).

G. N. PHILLIPS, K. O'GRADY, AND J. C. LODDER.
Magnetization reversal at elevated temperatures in Co/Pt multilayer thin films.
J. Phys. D-Applied Physics 34, 2960-2971 (2001).

T. HUGHES, K. O'GRADY, H. LAIDLER, AND R. W. CHANTRELL.
Thermal activation in exchange biased bilayers.
J. Magnetism Magnetic Materials 235, 329-336 (2001).

K. O'GRADY, N. W. OWEN, T. HUGHES, H. LAIDLER, AND A. K. PETFORD-LONG.
Magnetisation processes in exchange-biased systems.
J. Magnetism Magnetic Materials 226, 1798-1799 (2001).

T. HUGHES, K. O'GRADY, and others (7).
Magnetization reversal in the pinned layer of PtMnCr/NiFe exchange biased bilayers.
J. Applied Phys. 89, 6591-6593 (2001).

T. HUGHES, H. LAIDLER, AND K. O'GRADY.
Thermal activation of magnetization reversal in spin-valve systems.
J. Applied Phys. 89, 5585-5591 (2001).

A. M. GOODMAN, K. O'GRADY, H. LAIDLER, N. W. OWEN, X. PORTIER, AND A. K. PETFORD-LONG.
Magnetization reversal processes in exchange-biased spin- valve structures.
IEEE Trans. On Magnetics 37, 565-570 (2001).
 

Kevin O'Grady

Summary of expertise

  • Magnetic Materials