Dr
Ross
Stewart
MAPS Instrument Scientist
(01235) 446287
No
ross.stewart@stfc.ac.uk
No
RAL R3,2.06
No
07557-012585
No

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​MAPS Instrument S​​cientist

​Exciations and Polarized Neutron Group​​​





Recent Public​​ations

Anisotropic spin fluctuations in detwinned Fe​Se

Nature Materials

Quenching of Long Range Or​​der and the Mn3+ Ordered Moment 

in the Layered Antiferromagnet, BaxSr1–xLaMnO4. A Polarized Neutron Scattering Study

Inorganic Chemistry

2019-04 | journal-article

Upgrade to the MAPS neutron time-of-f​​​light chopper spectrometer

Review of Scientific Instruments

Transverse and longitudinal spin-fluctuations in INVAR Fe0.65Ni0.35​​

Journal of Physics: Condensed Matter

Magnetic ground state of Dy3+ in ​​D​​yNiAl4

AIP Advances

Spin correlations in the dipolar ​​pyrochlore antiferromagnet Gd2Sn2O7
Journal of Physics: Condensed Matter​
2017 | journal-article

  • Conformation-controlled hydrogen storage in t​​he CAU-1 metal-organic framework
  • Physical Chemistry Chemical Physics
  • 2016 | journal-article
  • DOI: 10.1039/c6cp05310f
  • WOSUID: WOS:000387024300027

Neutron polarisation analysis of Polymer: ​Fullerene blends for organic photovoltaics
Polymer
2016 | journal-article


Research Interests

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S​truct​​ure and dynamics of frustrated magnets


​Frustrated magnets are fascinating model systems in which the lattice topology and/or mixed magnetic interactions can lead to an extensively degenerate magnetic ground state. This leads to novel magnetic structural and dynamical properties in these materials.  Ross has, over the years, investigated various metallic frustrated magnets (β-Mn, YMn2, INVAR) mainly using neutron polarization analysis,  inelastic neutron scattering and muon spin relaxation (μSR) techniques.  He is also interested in the magnetic structural and dynamical properties of antiferromagnetic pyrochlore lattices (Gd2Ti2O7, Gd2Sn2O7) and kagome lattice (herbertsmithite, swedenborgite) materials. This work is done in collaboration with  Dr Joe Paddison (ORNL) and Dr. Andrew Goodwin (Oxford), addition to various other UK and international research teams.

Selected Publications:​

Spin correlations in the dipolar pyrochlore antiferromagnet Gd2Sn2O7
Journal of Physics-Condensed Matter
2017 | journal-article
DOI: 10.1088/1361-648X/aa5d2e

Emergent Frustration in Co-doped beta-Mn
  • Physical Review Letters
  • 2013 | journal-article

Pair correlations, short-range order, and dispersive excitations in the quasi-kagome quantum magnet volborthite
Physical Review B
2011 | journal-article

Spin dynamics, short-range order, and spin freezing in Y0.5Ca0.5BaCo4O7
Physical Review B
2011 | journal-article
Structural and dynamical study of moment localization in beta-Mn1-xInx
Physical Review B
2010 | journal-article
  • DOI: 10.1103/PhysRevB.82.144439

  • Scale-Free Antiferromagnetic Fluctuations in the s=1/2 Kagome Antiferromagnet Herbertsmithite
  • Physical Review Letters
  • 2009 | journal-article
Neutron polarization analysis study of the frustrated magnetic ground state of beta-Mn1-xAlx
Physical Review B
2008 | journal-article

Phase transitions, partial disorder and multi-k structures in Gd2Ti2O7
Journal of Physics-Condensed Matter
2004 | journal-article​
DOI: 10.1088/0953-8984/16/28/L01​​​​​


Non-Fermi-liquid behavior of electron-spin fluctuations in an elemental paramagnet
  • Physical Review Letters​
2002 | journal-article


​Polarized Neutron Scatte​​ring

Between 1998 and 2008, Ross worked at the Institut Laue-Langevin in Grenoble, where he led the redesign and reconstruction of the diffuse scattering spectrometer, D7, as part of the ILL Millennium Programme.   He designed a novel supermirror spin-analyser array for D7 which provided a factor of 60 increase in count-rate of this instrument.  At ISIS, from 2010-2017 Ross led the projects to bring 3He MEOP spin-filters to beamlines such as LARMOR and LET.  The LET spectrometer has recently been equiped with neut​ron polarization analysis using a combination of a supermirror polarizer and 3He wide-angle analyser system.  First experiments are now being performed, and Ross now provides experimental support.  

Selected Publications:​

Transverse and longitudinal spin-fluctuations in INVAR Fe0.65Ni0.35
Journal of Physics: Condensed Matter
2019-01-16 | journal-article

Neutron polarisation analysis of Polymer: Fullerene blends for organic photovoltaics
Polymer
2016 | journal-article
​​
Gener
alization of the classical xyz-polarization analysis technique to out-of-plane and inelastic scattering
Review of Scientific Instruments
2013 | journal-article

Disordered materials studied using neutron polarization analysis on the multi-detector spectrometer, D7
Journal of Applied Crystallography
2009 | journal-article
Magnetic structure of greigite (Fe3S4) probed by neutron powder diffraction and polarized neutron diffraction
Journal of Geophysical Research-Solid Earth
2009 | journal-article
PASTIS: An insert for polarization analysis studies on a thermal inelastic spectrometer
PHYSICA B-CONDENSED MATTER
2006 | journal-article
Large solid-angle polarisation analysis at thermal neutron wavelengths using a He-3 spin filter
Nucl. Inst. Meth. Phys. Res. A
2002 | journal-article



Co-funded Research Students

Philip Welch (University of Oxford) 2015-
Toby Willis (Royal Holloway) 2013-2016
Joe Paddison (Univeristy of Oxford) 2012-2016
Giovanni Pasquino (Royal Holloway) 2011-2015
Clare Leavey (University of Southampton) 2004-2008
Judith Preston (University of Leeds) 1999-2002
Charlotte Anderson (University of Liverpool) 1998-1999​​


​​External Bodies

  • ​Chair: Magnetism : inelastic applications and spectroscopy panel, MLZ
  • Editorial board: J. Phys: Condens. Matter (Magnetism section)
  • Member of the Institute of Physics (CPhys MInstP)


​Teac​hing

ORCID

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