Neutrinoless double beta decay (0n2b) is a theoretical nuclear transition, whose observation would become a major milestone in particle, and in particular, neutrino physics. This process, if it exists, violates lepton number conservation law and confirms Majorana nature of neutrino. The detection of 0n2b is a challenging task, since it is a very rare decay (T1/2>10^26 years), and the experiments require high detection efficiency, energy resolution, radiopurity, large mass and very low background levels. Several ton-scale experiments are in preparation, but in paralell, new approaches have to be investigated for higher sensitivity levels. The TINY project proposes new detection technology, based on cryogenic detectors (measured at mK temperatures). The thesis subject will be mainly dedicated to the development of new thermal sensors, Zr- and Nd-containing detectors characterization, performance evaluation and evaluation of technology applicability for a ton-scale experiment. The student will develop skills on operation of cryogenic facility, signal processing, data analysis and simulations. Finally, a demonstrator will be prepared with the goal to set new limits on 0n2b for 96-Zr and 150-Nd, and perform precision measurements of 2n2b decay.