Pinch Points and Kasteleyn Transitions: How Spin Ice Changes its Entropy (2007)
Fennell, T., Bramwell, S. T., McMorrow, D. F., Manuel, P.
Complex disordered states - from liquids and glasses to exotic quantum matter - are ubiquitous in nature. Their key properties include finite entropy, power-law correlations and emergent organising...
Pinch points and Kasteleyn transitions in kagome ice (2007)
Fennell, T., Bramwell, S.T., McMorrow, D.F., Manuel, P., Wildes, A.R.
Complex disordered states—from liquids and glasses to exotic quantum matter—are ubiquitous in nature. Their key properties include finite entropy, power-law correlations and emergent organizing...
Competition Between Exchange and Anisotropy in a Pyrochlore Ferromagnet (2007)
Champion, J. D. M., Bramwell, S. T., Holdsworth, P. C. W., Harris, M. J.
The Ising-like spin ice model, with a macroscopically degenerate ground state, has been shown to be approximated by several real materials. Here we investigate a model related to spin ice, in which...
Universal Magnetic Fluctuations with a Field Induced Length Scale (2007)
Portelli, B., Holdsworth, P. C. W., Sellitto, M., Bramwell, S. T.
We calculate the probability density function for the order parameter fluctuations in the low temperature phase of the 2D-XY model of magnetism near the line of critical points. A finite correlation...
Magnetic correlations in the 2D S=5/2 honeycomb antiferromagnet MnPS3 (2007)
Ronnow, H. M., Wildes, A. R., Bramwell, S. T.
MnPS3 is a quasi-2D S = 5/2 antiferromagnet on a honeycomb lattice. Using an energy integrating neutron scattering technique, we have measured the structure factor S(k) of the instantaneous magnetic...
Magnetocaloric Study of Spin Relaxation in `Frozen' Dipolar Spin Ice Dy2Ti2O7 (2006)
Orendac, M., Hanko, J., Cizmar, E., Orendacova, A., Shirai, M., Bramwell, S. T.
The magnetocaloric effect of polycrystalline samples of pure and Y-doped dipolar spin ice Dy2Ti2O7 was investigated at temperatures from nominally 0.3 K to 6 K and in magnetic fields of up to 2 T. As...
Temperature dependent fluctuations in the two-dimensional XY model (2005)
We present a detailed investigation of the probability density function (PDF) of order parameter fluctuations in the finite two-dimensional XY (2dXY) model. In the low temperature critical phase of...
Neutron scattering studies of the spin ices Ho2Ti2O7 and Dy2Ti2O7 in applied magnetic field (2005)
Fennell, T., Petrenko, O. A., Fak, B., Gardner, J. S., Bramwell, S. T., Ouladdiaf, B.
Neutron diffraction has been used to investigate the magnetic correlations in single crystals of the spin ice materials Ho2Ti2O7 and Dy2Ti2O7 in an external magnetic field applied along either the...
Neutron scattering studies of the spin ices Ho2Ti2O7 and Dy2Ti2O7 in applied magnetic field (2005)
Fennell, T, Petrenko, O A, Fak, B, Gardner, JS, Bramwell, S T, Ouladdiaf, B
Neutron diffraction has been used to investigate the magnetic correlations in single crystals of the spin ice materials Ho2Ti2O7 and Dy2Ti2O7 in an external magnetic field applied along either the...
Phase transitions, partial disorder and multi-k structures in Gd2Ti2O7 (2004)
Stewart, J.R., Ehlers, G., Wills, A.S., Bramwell, S.T., Gardner, J.S.
The geometrically frustrated antiferromagnet Gd2Ti2O7 exhibits magnetic behaviour of such complexity that it poses a challenge to both experiment and theory. Magnetic ordering commences at TN = 1.1 K...
Neutron Scattering Investigation of the Spin Ice State in Dy2Ti2O7 (2004)
Fennell, T., Petrenko, O. A., Fak, B., Bramwell, S. T., Enjalran, M., Yavors'kii, T., ...
Dy2Ti2O7 has been advanced as an ideal spin ice. We present a neutron scattering investigation of a sample of 162Dy2Ti2O7. The scattering intensity has been mapped in zero applied field in the hhl...
Positive and negative colossal magnetoresistance in a spin glass selenide spinel (2004)
Parker, D R, Green, M A, Bramwell, S T, Wills, A S, Gardner, J S, Neumann, D A
Neutron scattering investigation of the spin ice state in Dy2Ti2O7 (2004)
Fennell, T, Petrenko, O A, Fak, B, Bramwell, S T, Enjalran, M, Yavors'kii, T, ...
Dy2Ti2O7 has been advanced as an ideal spin ice material. We present a neutron scattering investigation of a single-crystal sample of (Dy2Ti2O7)-Dy-162. The scattering intensity has been mapped in...
Er2Ti2O7: Evidence of quantum order by disorder in a frustrated antiferromagnet (2003)
Champion, J D M, Harris, M J, Holdsworth, P C W, Wills, A S, Balakrishnan, G, Bramwell, S T, ...
Pressure-induced crystallization of a spin liquid (2002)
Mirebeau, I., Goncharenko, I.N., Cadavez-Peres, P., Bramwell, S.T., Gingras, M.J.P., Gardner, J.S.
Liquids are expected to crystallize at low temperature. The only exception is helium, which can remain liquid at 0 K, owing to quantum fluctuations1, 2. Similarly, the atomic magnetic moments (spins)...
Reply to Comment on " Universal Fluctuations in Correlated Systems" (2002)
Bramwell, S. T., Christensen, K., Holdsworth, P. C. W., Jensen, H. J., Lise, S., ...
Reply to the comment, cond-mat/0209398 by by N.W. Watkins, S.C. Chapman, and G. Rowlands
Field-induced partial order in the spin ice dysprosium titanate (2002)
Fennell, T, Petrenko, O A, Balakrishnan, G, Bramwell, S T, Champion, J D M, Fak, B, ...
Er2Ti2O7: Evidence of Order by Disorder in a Frustrated Antiferromagnet (2001)
Champion, J. D. M., Harris, M. J., Holdsworth, P. C. W., Wills, A. S., Balakrishnan, G., Bramwell, S. T., ...
Er_2Ti_2O_7 has been suggested to be a realization of the frustrated < 111 > XY pyrochlore lattice antiferromagnet, for which theory predicts fluctuation-induced symmetry breaking in a highly...
Spin ice state in frustrated magnetic pyrochlore materials (2001)
Bramwell, S.T., Gingras, M.J.P.
A frustrated system is one whose symmetry precludes the possibility that every pairwise interaction ("bond") in the system can be satisfied at the same time. Such systems are common in all areas of...
Lumsden, M. D., Dunsiger, S. R., Sonier, J. E., Miller, R. I., Kiefl, R. F., Jin, R., ...
We report transverse field and zero field muon spin rotation studies of the superconducting rhenium oxide pyrochlore, Cd2Re2O7. Transverse field measurements (H=0.007 T) show line broadening below...
Bramwell, S. T., Christensen, K., Holdsworth, P. C. W., Jensen, H. J., Lise, S., ...
We reply to the comment on our published paper `` Universal Fluctuations in Correlated Systems'',Phys. Rev. Lett. Vol; 84, p3744 (2000), by B. Zheng and S. Trimper, cond-mat/0109003. We argue that...
Field Induced Partial Order in the Spin-Ice Dysprosium Titanate (2001)
Fennell, T., Petrenko, O. A., Balakrishnan, G., Bramwell, S. T., Champion, J. D. M., Fak, B., ...
Neutron scattering has been used to investigate the magnetic correlations in the the spin ice material dysprosium titanate, Dy2Ti2O7. An isotopically enriched sample was used to minimise neutron...
Magnetic Susceptibility Study of the Heavy Rare Earth Stannate Pyrochlores (2001)
Bondah-Jagalu, V., Bramwell, S. T.
The series of magnetic rare earth pyrochlore stannates R2Sn2O7 (R = rare earth, except Ce and Pm) have been investigated by powder susceptibility measurements down to T =1.8 K. The results are...
Order in the Heisenberg Pyrochlore: The Magnetic Structure of Gd2Ti2O7 (2001)
Champion, J. D. M., Wills, A. S., Fennell, T., Bramwell, S. T., Gardner, J. S., Green, M. A.
The rare earth pyrochlore material Gd2Ti2O7 is considered to be an ideal model frustrated Heisenberg antiferromagnet with additional dipolar interactions. For this system there are several untested...
Competition Between Exchange and Anisotropy in a Pyrochlore Ferromagnet (2001)
Champion, J. D. M., Bramwell, S. T., Holdsworth, P. C. W., Harris, M. J.
The Ising-like spin ice model, with a macroscopically degenerate ground state, has been shown to be approximated by several real materials. Here we investigate a model related to spin ice, in which...
Universal Magnetic Fluctuations with a Field Induced Length Scale (2001)
Portelli, B., Holdsworth, P. C. W., Sellitto, M., Bramwell, S. T.
We calculate the probability density function for the order parameter fluctuations in the low temperature phase of the 2D-XY model of magnetism near the line of critical points. A finite correlation...
Spin Correlations in Ho$_{2}$Ti$_{2}$O$_{7}$: a Dipolar Spin Ice System (2001)
Bramwell, S. T., Harris, M. J., Hertog, B. C. Den, Gingras, M. J. P., Gardner, J. S., McMorrow, D. F., ...
The pyrochlore material $\rm Ho_{2}Ti_{2}O_{7}$ has been suggested to show ``spin ice'' behaviour. We present neutron scattering and specific heat results that establish unambiguously that...
Order in the Heisenberg pyrochlore: The magnetic structure of Gd2Ti2O7 (2001)
Champion, J D M, Wills, A S, Fennell, T, Bramwell, S T, Gardner, J S, Green, M A
Spin correlations in Ho2Ti2O7: A dipolar spin ice system (2001)
Bramwell, S T, Harris, M J, Den Hertog, B C, Gingras, M J P, Gardner, J S, McMorrow, D F, ...
Bramwell, S. T., Holdsworth, P. C. W., Peysson, S., Portelli, B., ...
We study the probability density function for the fluctuations of the magnetic order parameter in the low temperature phase of the XY model of finite size. In two-dimensions this system is critical...
Universal Fluctuations in Correlated Systems (1999)
Bramwell, S. T., Christensen, K., Holdsworth, P. C. W., Jensen, H. J., Lise, S., ...
The probability density function (PDF) of a global measure in a large class of highly correlated systems has been suggested to be of the same functional form. Here, we identify the analytical form of...
Magnetic structures of highly-frustrated pyrochlores (1998)
Harris, M J, Bramwell, S T, McMorrow, D F, Zeiske, T, King, P J C
Liquid-gas critical behaviour in a frustrated pyrochlore ferromagnet (1998)
Harris, M J, Bramwell, S T, Holdsworth, P C W, Champion, J D M
Geometrical frustration in the ferromagnetic pyrochlore Ho2Ti2O7 (1997)
Harris, M J, Bramwell, S T, McMorrow, D F, Zeiske, T, Godfrey, K W