ESR study of the (super)conducting charge-transfer salts β^''-(ET)4-[(H3-O)M-(C2-O4)3]S
Abstract
We present a spin resonance investigation of the family of quasi- two-dimensional organic (super)conductors &''circ; -(ET)4-[(H3-O)M-(C2-O4)3]S (M = Cr^ 3+, Fe^3+; S is a guest molecule). The spin systems are probed by means of both resonant cavity perturbation and field modulation techniques in the frequency range 50-313 GHz. The role of the different solvent molecules in determining the degree of spin-orbit coupling and the local symmetry at the metal ion site is established. Intensities, positions and widths of the resonant lines reveal significant modifications of the spin-orbit coupling, and of the inter- and intra-ionic spin-spin interactions below T=10K. Despite the onset of a weak antiferromagnetic internal field at low temperature, the ultimate narrowing of the lines suggests spin-lattice interactions are still the dominant relaxation process. Additional lineshifts observed below B = 2.5 T and T = 4 K, attributed to the presence of diamagnetic currents in the mixed state of the superconducting samples, provide a threshold for full field penetration within the ``insulating" anion layers.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2007
- Bibcode:
- 2007APS..MAR.R1179N