  Magnetic nanoparticles (MNPs) have excellent magnetic-temperature
characteristic. However, current temperature measurement based on MNPs is
interfered by concentration. Utilizing the electron spin resonance (ESR), we
propose a highly sensitive temperature measurement method without concentration
coupling. The anisotropic field is affected by temperature, thus affecting the
g-value. The influence of the MNP concentration, size, and the data analysis
method on temperature estimation are studied. The optimal temperature
sensitivity is achieved with 15-nm MNPs while Gaussian smoothing method allows
an optimal accuracy at Fe concentration of 5 mg/ml with a root mean squared
error of 0.07 K.
