Thermomagnetic mechanism of phase change materials for reconfigurable sensing

Phase change materials (PCMs) offer transformative potential for reconfigurable sensing due to their reversible structural transitions and dramatic property changes. However, their practical implementation remains constrained by reliance on direct Joule heating, which leads to high power consumption, complex electronics, and limited miniaturization—particularly problematic for biomedical, wearable, and harsh-environment applications. This paper proposes a paradigm shift toward contactless, energy-efficient activation using the magneto-caloric effect (MCE) in PCM composites. Through a unified theoretical and experimental analysis, we formalize thermomagnetic coupling mechanisms using Landau free energy, entropy-enthalpy compensation, and magnetocaloric formulations to enable remote phase switching via alternating magnetic fields. Key findings demonstrate that spin-lattice coupling reduces switching energy by up to 45% compared to thermal-only methods, while PCM-based sensors achieve multistate responsivity to thermal and magnetic stimuli with high cyclability (\: >10^5 cycles) and small response times. A detailed comparative analysis of PCM families—including chalcogenides, VO₂, and emerging composites—informs material selection for tailored applications. The work further demonstrates scalable, low-power, and spatially precise reconfiguration for adaptive sensors across optical, photonic, infrared, communication, biomedical, environmental, and space technology domains. By overcoming fundamental barriers in power efficiency and integration, this study lays the groundwork for next-generation intelligent sensing systems that are energy-efficient, remotely reconfigurable, and multifunctional.