MAGNETIC AND ELECTRICAL CHARACTERISTICS OF MNAS FILMS GROWN BY METALORGANIC CHEMICAL-VAPOR-DEPOSITION

The magnetic and electrical property changes associated with the phase transition in MnAs have been measured in uncracked material by using thin films grown on to sapphire substrates by metal organic chemical v apour deposition. The films exhibited a first-order transition with Cu rie points in the range 35-47+/1 degrees C. An increase of approximate ly 60% in the electrical resistivity of the films was measured on heat ing through the phase transition. The Curie temperature of the films i ncreased with an applied magnetic field by approximately 1.2 degrees C in a field of 600 kA m(-1). This shift in Curie temperature with appl ied magnetic field also produced a magnetoresistance effect with a max imum value of 2.24% at 600 kA m(-1). The values of these parameters ar e shown to be dependent upon the growth conditions of the films.