The Ever-Higher Blocking Temperature: Misconceptions and Self-Defeating Successes in Single-Molecule Magnetism

Over the past three decades, Single-Molecule Magnets (SMMs) have demonstrated consistently higher barriers for magnetization reversal (U_eff) and blocking temperatures (T_B), exhibiting extremely slow magnetic relaxation at low temperatures. This and other associated phenomena, provided impetus for significant advances in Molecular Magnetism, both theoretically and experimentally. In the applicative realm, and due to their long spin-lattice relaxation times, SMMs are simultaneously considered as the ultimate limit for high-density magnetic information storage media, and as potential candidates for spin-based qubits. Accordingly, synthetic and physical coordination chemists dedicate considerable means refining molecules in the pursuit of such applications. However, current and optimistically projected blocking temperatures are far too small for realistic information storage, while being at the same time far too large for efficient qubit initialization. This effectively places SMMs in an applicative "dead man's land". This Viewpoint highlights these issues drawing a distinction between the fundamental and applicative interest in SMM research.