Professor Stephen Blundell: Publications

Spin freezing and magnetic inhomogeneities in bilayer manganites

Physical Review Letters 89 (2001) 277601 4pp

Authors:

SJ Blundell, A I Coldea, C A Steer, J F Mitchell

ChemInform Abstract: Chemically Induced Magnetism and Magnetoresistance in La0.8Sr1.2Mn0.6Rh0.4O4 .

ChemInform Wiley 32:46 (2001) no-no

Authors:

Peter D Battle, Anthony MT Bell, Stephen J Blundell, Amalia I Coldea, Edmund J Cussen, Georgina C Hardy, Ishbel M Marshall, Matthew J Rosseinsky, Christopher A Steer

Magneto-optics of organic crystalline field effect transistors

(2001)

Authors:

A Ardavan, SJ Blundell, J Singleton

Colossal magnetoresistance in the layered chromium sulfide Cr2S3-x (x=0.08)

Physical Review B - Condensed Matter and Materials Physics 64:13 (2001) 1324021-1324024

Authors:

P Vaqueiro, AV Powell, AI Coldea, CA Steer, IM Marshall, SJ Blundell, J Singleton, T Ohtani

Abstract:

We report structural, magnetic, and magnetotransport properties of the two-dimensional chromium sulfide Cr2S2.92, which contains both Cr3+ and Cr2+ ions. Below its magnetic-ordering temperature (TN=118 K), Cr2S2.92 exhibits a weak spontaneous magnetization with a maximum around 90 K and a value of 0.013(4) μB per Cr ion at 5 K. The resistivity and magnetoresistance exhibit pronounced local maxima around TN (MR=48% in a field of 14 T). The magnetotransport properties are discussed in terms of magnetic-polaron formation.

Chemically induced magnetism and magnetoresistance in La(0.8)Sr(1.2)Mn(0.6)Rh(0.4)O(4).

J Am Chem Soc 123:31 (2001) 7610-7615

Authors:

PD Battle, AM Bell, SJ Blundell, AI Coldea, EJ Cussen, GC Hardy, IM Marshall, MJ Rosseinsky, CA Steer

Abstract:

It is shown by magnetometry and microSR spectroscopy that short-range magnetic interactions between the Mn cations in the nonmetallic K(2)NiF(4)-like phase La(0.8)Sr(1.2)Mn(0.6)Rh(0.4)O(4) become significant below approximately 200 K. Negative magnetoresistance (rho/rho(0) approximately 0.5 in 14 T at 108 K) is apparent below this temperature. Neutron diffraction has shown that an applied magnetic field of 5 T is sufficient to induce saturated (3.38(7)mu(B) per Mn) long-range ferromagnetic ordering of the atomic moments at 2 K, and that the induced ordering persists up to a temperature of 50 K in 5 T. Spin glass behavior is observed below 20 K in the absence of an applied field. The induced magnetic ordering is attributed to the subtle changes in band structure brought about by the external field, and to the controlling influence of Rh(3+) over the relative strength of competing magnetic exchange interactions.

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