6533b861fe1ef96bd12c4c15

RESEARCH PRODUCT

Spin-lattice relaxation via quantum tunneling in anEr3+-polyoxometalate molecular magnet

Oscar MonteroSalvador Cardona-serraThomas SchurigCarlos Martí-gastaldoEugenio CoronadoFernando LuisM. J. Martínez-pérezJuan M. Clemente-juanDietmar DrungJavier Sesé

subject

PhysicsCondensed matter physicsSpinsPhononRelaxation (NMR)Spin–lattice relaxationOrders of magnitude (data)Condensed Matter PhysicsHyperfine structureQuantum tunnellingElectronic Optical and Magnetic MaterialsSpin-½

description

We investigate the mechanism of spin-lattice relaxation of Er ions encapsulated in polyoxometalate clusters, which below 4 K can only reverse its spin via quantum tunneling processes. The temperature-independent rate −1 is, at zero field, ten orders of magnitude larger than the rates predicted for direct phonon-induced processes. In addition, we observe that −1 is suppressed by external magnetic bias and hyperfine interactions but enhanced by increasing the concentration of Er ions. The observed relaxation agrees with predictions for pure quantum tunneling, showing that this phenomenon drives the thermalization of electronic spins. A possible link between these two phenomena is discussed, involving the collective emission of phonons from particular spin configurations attained via quantum tunneling.

https://doi.org/10.1103/physrevb.82.060403