Presently we evaluated the natural relaxation frequency of the spin angular momentum of Fe3O4 and hemozoin superparamagnetic (SP) nanoparticles in D2O solutions in function of the sample temperature. The sample was composed of 1% H2O in D2O with dispersed Fe3O4 or hemozoin nanoparticles at variable number density. The natural relaxation frequencies are in the sub-MHz and MHz range for the Fe3O4 and hemozoin nanoparticles, respectively. We studied resonance heating of the same samples. We found that scanning the external magnetic field strength in a constant-frequency radio-frequency (RF) electromagnetic field, with its magnetic field component perpendicular to the external magnetic field, we obtain resonant heating at the magnetic field strength of 50 or 100 Gs for the RF excitation at 150 or 300 MHz, respectively. The measured resonance line has a Lorentzian form, with the heating amplitude dependent on the number density of SP nanoparticles, RF power and time. The resonance width correlates with the natural relaxation frequency of the spin angular momentum of the SP nanoparticles. We describe a theoretical model explaining the experimental results. As the achievable heating rate is directly proportional to the spin relaxation rate of the SP nanoparticles, we expect two orders of magnitude higher heating rates in suspensions based on water with natural isotopic composition.