Heat Capacity At The Field-Induced Ferromagnetic Transition In Eu0.58sr0.42mno3

Eu0.58Sr0.42MnO3 is found to own a wide variety of magnetic structures, and two subsequent magnetic transitions, a PM-AFM (paramagnetic-antiferromagnetic) transition followed by an AFM-FM (ferromagnetic) transition, are observed under proper magnetic field. It is found that the thermal response of heat capacity to the AFM-FM transition is negligibly small when this transition is well below the PM-AFM transition, and grows rapidly as the Curie temperature sweeps through the broad PM-AFM transition under the driving of magnetic field. This result indicates that the magnetic anomaly in heat capacity comes exclusively from the PM-FM transition, and the field-induced AFM-FM transition has essentially no thermal effects. A qualitative explanation for this result has been given based on the mean field theory. (C) 2005 American Institute of Physics.