Stoner-enhanced paramagnetism in tungsten tetraboride

We demonstrate that tungsten tetraboride (WB4), a heavy transition metallic compound without magnetic atoms, is an exchange-enhanced paramagnet revealed by the magnetization and specific heat measurements. WB4 has a small effective magnetic moment of 0.53 mu(B)/fu. The high magnetic susceptibility in the magnitude of 1 memu (mol.Oe)(-1) below 10 K obeys quadratic temperature dependence. The upturn behavior of C-P/T versus T-2 at low temperatures is attributed to the electron-paramagnon interactions. A high Stoner enhancement parameter, Z = 0.93, was derived to explain the enhanced paramagnetism based on the Stoner model.