Contribution (Poster) TNT2009 September 07-11, 2009 Barcelona-Spain MAGNETIZATION OF DIAMOND-GRAPHENE FLAKES COMPOSITES I.A. Denisov 1 , P.I. Belobrov 2 , S.S. Tsegelnik 1 , K.A. Shaikhutdinov 2 , D.A. Znak 1 , D.A. Balaev 2 , O.A. Bayukov 2 , S.B. Korchagina 3 , E.A. Petrakovskaya 2 , D.A. Velikanov 2 , N.V. Volkov 2 , S.K. Gordeev 3 1 Siberian Federal University, 660074 Krasnoyarsk, Russia 2 Kirensky Institute of Physics & Institute of Biophysics SB RAS, 660036 Krasnoyarsk, Russia 3 Central Research Institute of Material, 191014 St. Petersburg, Russia peter.belobrov@gmail.com Magnetic properties of composites from nanodiamond and pyrocarbon (NDC) with the factor γ = mass ratio of sp2/sp3 phases have been studied. Solid bulk porous NDC is made as described in [1]. NDC is semiconductor with the electrical conductivity has changed by 12 orders of magnitude that are controlled by the ratio γ from 0 to 80 % [2]. NDC has intrinsic paramagnetic properties that are permanent for all values of γ [3]. Taking into attention the recent analysis of experimental errors in the observation of nanoscale magnetism [4] we report here the results detailed study the magnetization of NDC by a few methods: wide-angle X-ray diffraction, EPR, Mossbauer, Raman and FTIR spectroscopy. Magnetic measurement was made on the different type of magnetometers (vibration, SQUID, PPMS). The bulk magnetization and 13 C NMR spin-lattice relaxation of nanodiamond powder samples have been studied [5] and nonaromatic core-shell structural model of nanodiamond particles has been proposed recently [6]. The total magnetization of NDC can be explained in terms of contributions from (1) the temperature independent different diamagnetic and paramagnetic effects of nanodiamond and graphene flakes χ ∑ , (2) the strong temperature dependent paramagnetic effect of unpaired electrons of nanodiamond and tetrahedral Fe-centers into nanodiamond structure, and (3) ferromagnetic-like contributions from magnetic impurities M ferro . The results are shown in the figures 1 and 2 and table 1. Main our result is following: NDC is magnetic semiconductor with phantom doping by Fe of nanodiamond. The principal possibilities of doping by Cr and S using porous structure of NDC have been illustrated here in the first time. Recent synthesis of luminescence nanodiamonds from carbon black of 99.9 % purity [7] shows useful method to delete impurities naturally present in detonation nanodiamond. This research was supported by RFBR Grants 07-04-01340-а and 08-02-00259-a, ME&S of RF Grant No. 2.2.2.2/5309 and U.S. CRDF Grant RUX0-002-KR-06/BP4M02. References: [1] S. K. Gordeev, S. G. Zhukov, P. I. Belobrov, A. N. Smolianinov, and Ju. P. Dikov, U.S. Patent No. 6 083 614 (4 July 2000), Russian Patent No. 95116683 (27 September 1995). [2] S.K. Gordeev, P.I. Belobrov, N.I. Kiselev, E.A. Petrakovskaya, T.C. Ekstrom, Mat. Res. Soc. Proc., 638 (2001) F18.4.1-6. [3] P.I. Belobrov, S.K. Gordeev, E.A. Petrakovskaya and O.V. Falaleev, Doklady Physics, 46 (2001) 459. [4] M. A. Garcia, E. Fernandez Pinel, J. de la Venta, A. Quesada, V. Bouzas, J. F. Fernández, J. J. Romero, M. S. Martín González, and J. L. Costa-Krämer, J. Appl. Phys. 105 (2009) 013925. [5] E. M. Levin, X. W. Fang, S. L. Bud'ko, W. E. Straszheim, R. W. MeCallum, and K. Schmidt-Rohr, Phys. Rev. B. 77 (2008) 054418.