Nanosecond spin lifetimes in single- and few-layer graphene-hBN   heterostructures at room temperature
  We present a new fabrication method of graphene spin-valve devices which yields enhanced spin and charge transport properties by improving both the electrode-to-graphene and graphene-to-substrate interface. First, we prepare Co/MgO spin injection electrodes onto Si$^{++}$/SiO$_2$. Thereafter, we mechanically transfer a graphene-hBN heterostructure onto the prepatterned electrodes. We show that room temperature spin transport in single-, bi- and trilayer graphene devices exhibit nanosecond spin lifetimes with spin diffusion lengths reaching 10$\mu$m combined with carrier mobilities exceeding 20,000 cm$^2$/Vs. 
Marc Dr\"ogeler, Frank Volmer, Maik Wolter, Bernat Terr\'es, Kenji   Watanabe, Takashi Taniguchi, Gernot G\"untherodt, Chris...
cond-mat.mes-hall