Thermodynamic properties of (Ca,Sr)2RuO4 in magnetic fields

Abstract We have studied the influence of a magnetic field on the thermodynamic properties of Ca 2 - x Sr x RuO 4 in the intermediate metallic region with tilt and rotational distortions ( 0.2 ⩽ x ⩽ 0.5 ) . We find strong and anisotropic thermal expansion anomalies at low temperatures, which are suppressed and even reversed by a magnetic field. The metamagnetic transition of Ca 1.8 Sr 0.2 RuO 4 is accompanied by a large magnetostriction. Furthermore, we observe a strong magnetic-field dependence of c p / T and that can be explained by magnetic fluctuations.