High magnetic field magnetization and specific heat of the 2D spin–dimer system SrCu2(BO3)2

We measured the magnetization versus field of SrCu2(BO3)2 using a 45T, 400ms pulsed magnet. By achieving good thermal coupling of the sample to the 3He and 4He baths, we obtained a realistic temperature-dependence for the 1/8, 1/4 and 1/3 magnetization plateaux. In addition, we measured the low temperature specific heat in continuous magnetic fields up to 18T. We found that a contribution attributed to singlet spin–dimer excitations is …