Magnetic torque measurements of TPP[Fe(Pc)Br2]2

Abstract Magnetic torque measurements of TPP[Fe(Pc)Br 2 ] 2 are reported. The torque curves for the magnetic field rotated within the ac plane exhibit a two-fold symmetry. The temperature dependences of the torque amplitudes divided by the square of the field strength ( τ φ =45 / B 2 ) exhibit a drastic field dependence below 12 K. This field dependence is attributable to the fluctuation in the spontaneous magnetization that appears below 4.5 K. The torque curves for the field rotated within the ab plane exhibit four-fold symmetry. The curves are sinusoidal above 18 K and exhibit saw-toothed shapes below ∼12 K and complicated shapes below 8 K. The complicated shapes suggest that both d-electrons and π-electrons form a magnetic order below 8 K.