Cent. Eur. J. Phys. • 8(4) • 2010 • 620-627 DOI: 10.2478/s11534-009-0140-7 Central European Journal of Physics Magnetic cluster developement in In 1−x Mn x Sb semiconductor alloys Research Article Lidia Rednic 1∗ , Iosif G. Deac 1 , Eugen Dorolti 1 , Marin Coldea 1 , Vasile Rednic 1 , Manfred Neumann 2 1 Babes-Bolyai University, Faculty of Physics, 4000084 Cluj-Napoca, Romania 2 University of Osnabrück, Fachbereich Physik, 49069 Osnabrück, Germany Received 16 March 2009; accepted 26 August 2009 Abstract: X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM) and magnetic measurements as a function of applied magnetic field and temperature for In 1−x Mn x Sb (0.05 x 0.2) system are reported. Magnetic measurements performed at high and small magnetic field in ZFC and FC indicate the coexistence of ferromagnetic In 1−x Mn x Sb solid solution and two types of mag- netic cluster: ferromagnetic MnSb and ferrimagnetic Mn 2 Sb. XPS valence band and Mn 2p core level spectra have confirmed the presence of MnSb and Mn 2 Sb phases. TEM images show some manganese antimonide phase microinclusions with dimension between (30-40) nm. PACS (2008): 75.50.Pp, 79.60.-i, 74.25.Ha, 75.60.Ej, 73.22.-f Keywords: magnetic semiconductors • XPS spectra • magnetic properties • hysteresis • clusters © Versita Sp. z o.o. 1. Introduction The doping of III-V semiconductors with 3d transition ele- ments creates ferromagnets, called magnetic semiconduc- tors. These materials continue to attract the interest of the scientific community, since they hold promise of ap- plications in a variety of spin-controlled devices [1]. The 1992 discovery of hole-mediated ferromagnetic order in (In,Mn)As [2] has motivated research on Mn-doped GaAs and other III-V host materials [3]. Indium antimonite (InSb) is a narrow gap semiconductor with an energy band gap of 0.17 eV at 300 K and 0.23 eV at 80 K. It crystallizes in the zinc-blende structure type with ∗ E-mail: lrednic@phys.ubbcluj.ro a 0.648 nm lattice constant. The undoped semiconductor possesses the largest ambient temperature electron mobil- ity (7.8 m 2 V −1 s −1 ), electron velocity, and ballistic length (up to 0.7 μm at 300 K) of any known semiconductor [4]. Ferromagnetism in In 1−x Mn x Sb (x∼ 0.02) with T c up to 20 K has been observed in films grown by Molecular Beam Epitaxy (MEB) [5]. Earlier studies on bulk In 1−x Mn x Sb, performed in the 0.01 x 0.06 concentration range [6], pointed out the presence in the investigated samples of an In 1−x Mn x Sb solid solution with T C < 10 K and also mi- croinclusions of manganese antimonide phase. These mi- croinclusions (clusters) might be identified as either ferro- magnetic MnSb or Mn 2 Sb, because in the phase diagram of Mn-Sb system there are only these two compounds and no solid solution. To complete the picture and explain the magnetic behaviour of these materials a study of bulk 620 Unauthenticated Download Date | 7/26/18 1:06 PM