MAGNATIC SEMICONDUCTOR THIN FILMS-MAGNETIC AND TRANSPORT PROPERTIES

摘要

Thin films of magnetic semiconductor Cd_(1-y)Cr_(2-2x)In_(2x+y)Se_4 have been investigated as the perspective element of near-infrared detector. It is soft magnetic material, the energetic structure is modified by the indium dilution level and magnetic interaction. Also the increase of lattice parameter and changes of the local atomic environments, with increasing the amount of In, is detected. For the CdCr_2Se_4 the magnetic state with reentrant transition (REE) is achieved. When indium substitutes Cr or Cd, we have the spin glass state (SG). The more complex type of magnetic ordering, the randomly canted state (RC) was found when In substitutes Cr and Cd. The basic photoconductivity parameters, as spectral voltage responsivity and detectivity were determined by lock-in measurement technique. It was found that for thin films in state with REE, the value of detectivity about 10~7 mHz~(1/2)W~(-1) is the order as for semiconductor materials.