Puzzling magnetic behavior of non-centrosymmetric superconductor Re$_{3}$W

We have studied magnetic properties of non-centrosymmetric superconductor Re$_{3}$W. Unlike ordinary BCS superconductors, annealed samples of Re$_{3}$W exhibit linear Abrikosov-like dependence of the equilibrium (M$_{eq})$ and non-equilibrium (M) magnetization on magnetic field H in an anomalously large range H$\approx $(0.1-1)H$_{c2}$. This behavior is drastically different for the quenched (``as prepared'') samples of Re$_{3}$W. Equilibrium magnetization was obtained by ``shaking'' the flux line lattice with an alternating transverse field. M$_{eq}$(H) curves show change in slope in about the same region of magnetic fields where the slopes of corresponding critical currents J$_{c}$(H) also change. In our talk, we discuss probable causes of these effects. ORNL is managed by UT-Battelle, LLC for USDOE under contract DE-AC05-00OR22725.