Calorimetric studies of a series of magnetic-field-induced spin density wave states in a quasi D = 1 metal

• Published in: Journal of magnetism and magnetic materials 1986-02, Vol.54, p.1418-1422
• Main Authors: Garoche, P., Pesty, F.
• Format: Article
• Language: English
• ISSN: 0304-8853
• DOI: 10.1016/0304-8853(86)90877-2

The high-field ( H < 6 T) low-temperature phase of the organic conductor (TMTSF) 2ClO 4 has been studied by measuring the specific heat of an oriented single crystal ( H in the c direction). Above a 3.5 T threshold-field, the electronic contribution to the specific heat shows clearly a second-order phase transition from a normal metal to a low temperature semi-metallic phase. A direct measurement of the field-dependent electronic specific heat reveals a series of magnetic-field-induced phase transitions. A phase diagram is obtained from the combination of these new data. The periodicity of the phase transitions is in good agreement with a two-dimensional transverse nesting for the spin density wave vector (2 k F, π/ b, π/ c). A partial reentrance of the normal metal between SDW states is observed above the threshold-field. The competition between diamagnetic energy and the best nesting for the spin density wave is shown to be responsible for the series of field-induced phase transitions and explains the anomalous Hall effect observed at high field.