Ferromagnetism in (In,Mn)As diluted magnetic semiconductor thin films grown by metalorganic vapor phase epitaxy

In1-xMnxAs diluted magnetic semiconductor thin films have been grown using metalorganic vapor phase epitaxy. Tricarbonyl(methylcyclopentadienyl)manganese was used as the Mn source. Nominally single-phase, epitaxial films were achieved with Mn content as high as x = 0.14 using growth temperatures T-g greater than or equal to 475 degreesC. For lower growth temperatures and higher Mn concentrations, nanometer scale. MnAs precipitates were detected within the In1-xMnxAs matrix. Magnetic properties of the films were investigated using a superconducting quantum interference device magnetometer. Room-temperature ferromagnetic order was observed in a sample with x = 0.1. Magnetization measurements indicated a Curie temperature of 333 K and a room-temperature saturation magnetization of 49 emu/cm(3). The remnant magnetization and the coercive field were small, with values of 10 emu/cm(3) and 400 Oe, respectively. A mechanism for this high-temperature ferromagnetism is discussed in light of the recent theory based on the formation of small clusters of a few magnetic atoms. (C) 2002 American Vacuum Society.