Quantum matter in high magnetic fields

Research group

Research theme

Sub department

About

Fermi-surface topology and the effects of intrinsic disorder in a class of charge-transfer salts containing magnetic ions, \beta''-(BEDT-TTF)_4[(H_3O)M(C_2O_4)_3]Y

(2003)

Authors:

AI Coldea, AF Bangura, J Singleton, A Ardavan, A Akutsu-Sato, H Akutsu, SS Turner, P Day
More details from the publisher

Non-adiabatic small polaron hopping in the n=3 Ruddlesden-Popper compound Ca4Mn3O10

(2003)

Authors:

J Lago, PD Battle, MJ Rosseinsky, AI Coldea, J Singleton
More details from the publisher

Synthesis and characterisation of Sr1.2Nd0.8Mn0.6Rh0.4O4

Journal of Materials Chemistry 13:5 (2003) 1166-1172

Authors:

DJ Gallon, PD Battle, SJ Blundell, AI Coldea, MJ Rosseinsky, C Steer

Abstract:

A polycrystalline sample of Sr1.2Nd0.8Mn0.6Rh0.4O4 has been synthesised and characterised by neutron diffraction, dc magnetometry, muon spectroscopy and magnetotransport measurements. Ir is an n = 1 member of the Ruddlesden-Popper (RP) An + 1BnO3n + 1 family, having tetragonal (I4/mmm) symmetry [a = 3.86418(6), c = 12.4414(2) Å]. Rh and Mn cations are disordered over the six-coordinate sites within the perovskite layers of the RP structure and the A sites are occupied by a disordered distribution of Nd and Sr. In contrast to the analogous compound Sr1.2La 0.8Mn0.6Rh0.4O4, which showed long range ferromagnetic ordering in an applied field ar 2 K, a spin-glass transition was observed ar 16 K for the Nd-containing compound. No long range magnetic order was observed ar 2 K. A maximum magnetoresistance of ∼ 30% in a 140 kOe field was found at 125 K.
More details from the publisher
More details

Magnetotransport measurements on beta ''-(BEDT-TTF)(4)[(H3O)Ga3+(C2O4)(3)](center dot) C6N5NO2

SYNTHETIC MET 137:1-3 (2003) 1313-1314

Authors:

AF Bangura, AI Coldea, J Singleton, A Ardavan, AK Klehe, A Akutsu-Sato, H Akutsu, SS Turner, P Day

Abstract:

Transport measurements have been carried out on single crystals of the charge transfer salt beta"-(BEDT-TTF)(4)[(H3O) Ga3+ (C2O4)(3)]. C6H5NO2, using magnetic fields of up to 33 T and temperatures down to 0.55 K. The material is found to be superconducting with T. 7.5 K and an in-plane critical field B-c2 greater than or equal to 33 T, and to exhibit Shubnikov-de Haas (SdH) oscillations. The temperature and angle dependence of the Shubnikov-de Haas oscillations and the upper critical field are reported, allowing information about the anisotropy of the upper critical field, effective mass m*, and the Fermi-surface (FS) of the material to be deduced.
More details from the publisher

Magnetotransport measurements on β"-(BEDT-TTF)4[(H3O)Ga3+(C2 O4)3]. C6H5NO2

Synthetic Metals 137:1-3 (2003) 1313-1314

Authors:

AF Bangura, AI Coldea, J Singleton, A Ardavan, AK Klehe, A Akutsu-Sato, H Akutsu, SS Turner, P Day

Abstract:

Transport measurements have been carried out on single crystals of the charge transfer salt β″-(BEDT-TTF)4[(H3O)Ga3+(C2 O4)3]. C6H5NO2, using magnetic fields of up to 33 T and temperatures down to 0.55 K. The material is found to be superconducting with Tc ≈ 7.5 K and an in-plane critical field Bc2 ≥ 33 T, and to exhibit Shubnikov-de Haas (SdH) oscillations. The temperature and angle dependence of the Shubnikov-de Haas oscillations and the upper critical field are reported, allowing information about the anisotropy of the upper critical field, effective mass m*, and the Fermi-surface (FS) of the material to be deduced.
More details from the publisher