Magnetism in the (Co1−xFex)2(OH)2(C8H4O4) solid solutions: a combined neutron diffraction and magnetic measurements study

Abstract

The magnetic properties of the solid solution (Co_1−xFe_x)₂(OH)₂(C₈H₄O₄) x = 0.25 (1), x = 0.5 (2), x = 0.75 (3), x = 0.88 (4) and of the pure iron compound x = 1.0 (5) (C2/m) were investigated by magnetic susceptibility measurements and neutron diffraction experiments. Magnetic measurements show that the pure iron compound is antiferromagnetic below T_N = 65 K. The AC susceptibility vs. temperature curves for the iron-cobalt solid solutions reveal a complicated magnetic behavior. This behavior is discussed with that of the pure cobalt compound which is known for stabilizing several magnetic states as a function of the temperature and of the applied field. These bimetallic compounds were also studied by magnetization vs. applied magnetic field (up to 9 T) and they appear to be a simple way to tune the giant hysteretic effect known for Co₂(OH)₂(C₈H₄O₄) at low temperature. The neutron diffraction study at 2 K reveals that in the pure iron compound the magnetic moments are aligned along the b axis. Several compositions of the hybrid solid solution were also investigated, the analysis of the data display a reorientation of the magnetic moment directions along the c axis for x < 0.50, as observed in the pure cobalt compound.