The nature of the magnetic order in Ca3Co2O6 (2008)
Agrestini, S., Chapon, L. C., Daoud-Aladine, A., Schefer, J., Gukasov, A., Mazzoli, C., ...
We present a detailed powder and single crystal neutron diffraction study of the spin chain compound Ca3Co2O6. Below 25 K, the system orders magnetically with a modulated partially disordered...
Tung, L. D., Ivanov, A., Schefer, J., Lees, M. R., Balakrishnan, G., Paul, D. McK
We report the results of magnetization, heat capacity and neutron scattering studies of LaVO3 single crystals. From the neutron diffraction studies, it was found that the compound is magnetically...
Electronic texture of the thermoelectric oxide Na0.75CoO2 (2008)
De Vaulx, C., Mayaffre, H., Berthier, C., Horvatic, M., Simonet, V., ...
From 59Co and 23Na NMR, we demonstrate the impact of the Na+ vacancy ordering on the cobalt electronic states in Na0.75CoO2: at long time scales, there is neither a disproportionation into 75 % Co3+...
Incommensurate magnetic ground state revealed by RXS in the frustrated spin system Ca3Co2O6 (2008)
Agrestini, S., Mazzoli, C., Bombardi, A., Lees, M. R.
We have performed a resonant x-ray scattering study at the Co pre-K edge on a single crystal of Ca3Co2O6. The measurements reveal an abrupt transition to a magnetically ordered state immediately...
Elliptical hole pockets in the Fermi surfaces of unhydrated and hydrated sodium cobalt oxides (2007)
Laverock, J., Dugdale, S. B., Duffy, J. A., Wooldridge, J., Balakrishnan, G., Lees, M. R., ...
The surprise discovery of superconductivity below 5K in sodium cobalt oxides when hydrated with water has caught the attention of experimentalists and theorists alike. Most explanations for its...
Tung, L D, Lees, M R, Balakrishnan, G, Paul, D McK
We report on a study of various RVO3 single-crystal samples (R = La, Nd, Sm, Gd, Er and Y) which show temperature-induced magnetization reversal. For compounds with lighter rare-earths (R = La, Nd...
Intraplanar Magnetic Excitations in Na0.5CoO2: An Inelastic Neutron Study (2006)
Wooldridge, J., Balakrishnan, G., Paul, D. McK., Frost, C., Bourges, P., Lees, M. R.
Inelastic neutron scattering measurements mapping the in-plane magnetic interactions of Na0.5CoO2 reveal dispersive excitations at points above an energy gap Eg = 11.5(5) meV at the superstructural...
The effect of externally applied pressure on the magnetic behavior of Cu2Te2O5(BrxCl{1-x})2 (2006)
Crowe, S. J., Lees, M. R., Paul, D. McK., Bewley, R. I., Taylor, J. W., McIntyre, G., ...
The effect of externally applied pressure on the magnetic behavior of Cu2Te2O5(BrxCl{1-x})2 with x = 0, 0.73 and 1, is investigated by a combination of magnetic susceptibility, neutron diffraction...
Wooldridge, J., Paul, D. McK., Balakrishnan, G., Lees, M. R.
We have measured the magnetic field (H
Crowe, S. J., Majumdar, S., Lees, M. R., Paul, D. McK., Bewley, R. I., Levett, S. J., ...
Neutron inelastic scattering investigations have been performed on the spin tetrahedral system Cu_2Te_2O_5X_2 (X = Cl, Br). We report the observation of magnetic excitations with a dispersive...
Temperature and field dependence of the spin magnetization density in SmMn2Ge2 (2005)
Bebb, A M, Taylor, J W, Duffy, J A, Banfield, Z F, Cooper, M J, Lees, M R, ...
Inelastic neutron scattering study of the spin-gap behaviour in Cu2Te2O5Br5 (2005)
Crowe, S J, Majumdar, S, Lees, M R, Paul, D McK, Adroja, D T, Levett, S J
Revised magnetic properties of CuFeO2 - a case of mistaken identity (2005)
Petrenko, O. A., Lees, M. R., Balakrishnan, G., De Brion, S., Chouteau, G.
Single crystals of the anisotropic Kagome staircase compounds Ni3V2O8 and Co3V2O8 (2004)
Balakrishnan, G., Petrenko, O. A., Lees, M. R., Paul, D. McK.
Compounds with a Kagome type lattice are known to exhibit magnetic frustration. Large single crystals of two compounds Ni3V2O8 and Co3V2O8, which are variants of a Kagome net lattice, have been grown...
Investigation of the Spin Density Wave in NaxCoO2 (2004)
Wooldridge, J., Paul, D. McK, Balakrishnan, G., Lees, M. R.
Magnetic susceptibility, transport and heat capacity measurements of single crystal NaxCoO2 (x=0.71) are reported. A transition to a spin density wave (SDW) state at Tmag = 22 K is observable in all...
Investigation of the field-treated magnetic state in Gd5Ge4 (2004)
Majumdar, S., Crowe, S. J., Paul, D. McK., Lees, M. R., Hardy, V.
At low temperatures, the intermetallic compound Gd$_5$Ge$_4$ shows a sharp field-induced transition into a ferromagnetic state around 25 kOe of applied field. The material remains in the field...
Quantum Tunneling of the Magnetization in the Ising Chain Compound Ca3Co2O6 (2004)
Maignan, A., Hardy, V., Hebert, S., Drillon, M., Lees, M. R., Petrenko, O., ...
The magnetic behavior of the Ca3Co2O6 spin chain compound is characterized by a large Ising-like character of its ferromagnetic chains, set on triangular lattice, that are antiferromagnetically...
Spin glass-like antiferromagnetic interactions in iron phosphate glasses (2004)
Shaw, J L, Wright, A C, Sinclair, R N, Marasinghe, G K, Holland, D, Lees, M R, ...
Majumdar, S., Hardy, V., Lees, M. R., Paul, D. McK., Rousseliere, H., Grebille, D.
The Heisenberg spin chain compound Sr3CuPtO6 is investigated by magnetic susceptibility and heat capacity measurements. Sr3CuPtO6 has an unconventional chain structure in the sense that i) the spin...
Magnetic phase diagram of the antiferromagnetic pyrochlore Gd2Ti2O7 (2003)
Petrenko, O. A., Lees, M. R., Balakrishnan, G., Paul, D. McK.
Gd2Ti2O7 is a highly frustrated antiferromagnet on a pyrochlore lattice, where apart from the Heisenberg exchange the spins also interact via dipole-dipole forces. We report on low-temperature...
Hardy, V., Majumdar, S., Crowe, S., Lees, M. R., Paul, D. McK., Herve, L., ...
Field-induced magnetization jumps with similar characteristics are observed at low temperature for the intermetallic germanide Gd5Ge4and the mixed-valent manganite Pr0.6Ca0.4Mn0.96Ga0.04O3. We report...
Oxygen Moment Formation and Canting in Li2CuO2 (2003)
Chung, E. M. L., McIntyre, G. J., Paul, D. McK., Balakrishnan, G., Lees, M. R.
The possibilities of oxygen moment formation and canting in the quasi-1D cuprate Li2CuO2 are investigated using single crystal neutron diffraction at 2 K. The observed magnetic intensities could not...
The role of electronic correlations on the phonon modes of MnO and NiO (2003)
Chung, E. M. L., Paul, D. McK., Balakrishnan, G., Lees, M. R., Ivanov, A., Yethiraj, M.
The possibility of magnetic-order induced phonon anisotropy in single crystals of MnO and NiO is investigated using inelastic neutron scattering. Below Tn both compounds exhibit a splitting in their...
Hardy, V., Lambert, S., Lees, M. R., Paul, D. McK.
Specific heat and magnetization measurements have been carried out under a range of magnetic fields on single crystals of Ca3Co2O6. This compound is composed of Ising magnetic chains that are...
Hardy, V., Lees, M. R., Maignan, A., Hebert, S., Flahaut, D., Martin, C., ...
Specific heat measurements were carried out on the closely related spin-chain oxides Ca3Co2O6 and Ca3CoRhO6. Both compounds consist of Ising magnetic chains that are arranged on a triangular lattice....
Growth of large single crystals of Rare Earth Hexaborides (2003)
Balakrishnan, G., Lees, M. R., Paul, D. McK.
Single crystal growth of several rare earth hexaborides has been carried out by the floating zone technique. A high power Xenon arc lamp image furnace was used for the crystal growth. Large high...
Anisotropic low field behavior and the observation of flux jumps in CeCoIn5 (2003)
Majumdar, S., Lees, M. R., Balakrishnan, G., Paul, D. McK
The magnetic behavior of the heavy fermion superconductor CeCoIn5 has been investigated. The low field magnetization data show flux jumps in the mixed state of the superconducting phase in a...
Raman scattering study of Nd1-xSrxMnO3 (x=0.3, 0.5) (2003)
Lemmens, P., Güntherodt, G., Pattabiraman, M., Rangarajan, G., Gnezdilov, V. P., ...
Comment on "Short-range magnetic interactions in the spin-ice compound Ho2Ti2O7" (2002)
Petrenko, O. A., Lees, M. R., Balakrishnan, G.
In their recent communication (Phys. Rev. B 64, 060406(R) (2001)) Cornelius and Gardner have reported the results of magnetization and susceptibility studies on single crystals of the pyrochlore...
Pressure Induced Change in the Magnetic Modulation of CeRhIn5 (2002)
Majumdar, S., Balakrishnan, G., Lees, M. R., Paul, D. McK, McIntyre, G. J.
We report the results of a high pressure neutron diffraction study of the heavy fermion compound CeRhIn5 down to 1.8 K. CeRhIn5 is known to order magnetically below 3.8 K with an incommensurate...
Taylor, J. W., Duffy, J. A., Bebb, A. M., Lees, M. R., Bouchenoire, L., Brown, S. D., ...
Non-resonant ferromagnetic x-ray diffraction has been used to separate the spin and orbital contribution to the magnetization density of the proposed zero-moment ferromagnet $Sm_{0.982}Gd_{0.018}...
Ferromagnetic fullerene (2002)
Wood, R A, Lewis, M H, Lees, M R, Bennington, S M, Cain, M G, Kitamura, N
Pressure effects on the magnetic and structural properties of layered manganites (2001)
Kamenev, K V, Marshall, W G, Lees, M R, Paul, D M, Balakrishnan, G, Tissen, V G, ...
High Magnetic Field Behaviour of the Triangular Lattice Antiferromagnet, CuFeO_2 (2000)
Petrenko, O. A., Balakrishnan, G., Lees, M. R., Paul, D. McK, Hoser, A.
The high magnetic field behaviour of the triangular lattice antiferromagnet CuFeO_2 is studied using single crystal neutron diffraction measurements in a field of up to 14.5 T and also by...
Pressure tuning of magnetic interactions in layered (La0.6Nd0.4)1.2Sr1.8Mn2O7 Manganite (2000)
Kamenev, K V, Lees, M R, Balakrishnan, G, Paul, D McK, Marshall, W G, Tissen, V G, ...