  TM-doped IrTe2(TM=Mn, Fe, Co, Ni) compounds were synthesized by solid state
reaction. Single crystal x-ray diffraction experiments indicate that part of
the doped TM ions (TM=Fe, Co, and Ni) substitute for Ir, and the rest
intercalate into the octahedral interstitial sites located in between IrTe2
layers. Due to the lattice mismatch between MnTe2 and IrTe2, Mn has limited
solubility in IrTe2 lattice. The trigonal structure is stable in the whole
temperature range 1.80<T<300K for all doped compositions. No long range
magnetic order or superconductivity was observed in any doped compositions
above 1.80K. A spin glass behavior below 10K was observed in Fe-doped IrTe2
from the temperature dependence of magnetization, electrical resistivity, and
specific heat. The low temperature specific heat data suggest the electron
density of states is enhanced in Fe- and Co-doped compositions but reduced in
Ni-doped IrTe2. With the 3d transition metal doping the trigonal a-lattice
parameters increases but the c-lattice parameter decreases. Detailed analysis
of the single crystal x-ray diffraction data shows that interlayer Te-Te
distance increases despite a reduced c-lattice. The importance of the Te-Te,
Te-Ir, and Ir-Ir bonding is discussed.
