Professor Stephen Blundell: Publications

Giant magnetic hardness in the synthetic mineral ferrimagnet K 2CoII 3(OH)2(SO4) 3(H2O)2

Chemistry of Materials 22:13 (2010) 4090-4095

Authors:

S Vilminot, PJ Baker, SJ Blundell, T Sugano, G André, M Kurmoo

Abstract:

Wepresent the synthesis, single-crystal X-ray (173 K) and powder neutron (2-30 K) structures and its thermal, optical and magnetic properties of K 2Co^II 3(OH)2(SO4) 2(H2O)2. It is a ferrimagnet (TC= 29.7 K) constructed of Co3(OH)2 diamond chains connected by sulfate and it displays hysteresis loops ranging from being soft with nearly zero coercivity between 29 and 10 K to very hard reaching coercive field exceeding 70 kOe at 1.8 K. This dramatic change is associated with the changes in domain shape due to the strong exchange anisotropy. Considerable frequency dependence of the acsusceptibilities is observed in the ordered state.Measurements on a single crystal have established the magnetic axes to be a-axis (easy), b-axis (intermediate), and c-axis (hard). © 2010 American Chemical Society.

Muon spin relaxation investigation of magnetic ordering in the hybrid organic-inorganic perovskites [(CH3)2NH2]M(HCOO)3, M = Ni,Co,Mn,Cu

(2010)

Authors:

PJ Baker, T Lancaster, I Franke, W Hayes, SJ Blundell, FL Pratt, P Jain, Z-M Wang, M Kurmoo

Superconductivity and fluctuating magnetism in quasi two-dimensional kappa-(BEDT-TTF)2Cu[N(CN)2]Br probed with implanted muons

(2010)

Authors:

T Lancaster, SJ Blundell, FL Pratt, JA Schlueter

A Paradigm Called Magnetism, by S. Dattagupta

Contemporary Physics Taylor & Francis 51:4 (2010) 380-380

Muon-spin relaxation and heat capacity measurements on the magnetoelectric and multiferroic pyroxenes LiFeSi2O6 and NaFeSi 2O6

Physical Review B Condensed Matter and Materials Physics 81:21 (2010)

Authors:

PJ Baker, HJ Lewtas, SJ Blundell, T Lancaster, I Franke, W Hayes, FL Pratt, L Bohatý, P Becker

Abstract:

We present the results of muon-spin relaxation and heat capacity measurements on LiFeSi2O6 and NaFeSi2O 6. In synthetic samples of both compounds we see a single muon oscillation frequency consistent with commensurate magnetic structures below TN. In contrast, for a specimen of naturally occurring NaFeSi2O 6, in which multiferroicity has been observed, a rapid Gaussian depolarization of the muon polarization is observed instead, showing that the magnetic structure in this case is more complex. Heat capacity measurements reproduce the phase diagrams previously derived from other techniques and demonstrate that the main contribution to the magnetic entropy is associated with the buildup of correlations in the quasi-one-dimensional Fe³⁺ chains. © 2010 The American Physical Society.

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