Magnetization reversal in chemically synthesized hexagonal cobalt microplatelets

We report the magnetization reversal modes in hexagonal cobalt microplatelets prepared via the solvothermal chemical synthesis method. Experimental results do not reflect any effect of anisotropy due to the shape of an individual platelet and the shape of the overall geometry of the ensemble of platelets. Micromagnetic simulations on a single hexagonal cobalt platelet demonstrate different kinds of reversal modes depending upon the direction of the applied magnetic field, whereas for a group of three platelets the reversal modes of a single platelet are manifested in a slightly modified form due to the weak magnetostatic interactions among themselves. In this case, a poor qualitative agreement is observed with the experimental hysteresis loops. A much better qualitative agreement with the experimental loops is observed for a random ensemble of seven platelets, and a strongly collective magnetization reversal is observed in this case.