Macroscopic quantum tunneling of magnetization explored by quantum-first-order reversal curves

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A method to study the fundamental problem of quantum double well potential systems that display magnetic hysteresis is proposed. The method, coined quantum-first-order reversal curve (QFORC), is inspired by the first-order reversal curve, based on the Preisach model for hysteresis. We successfully tested the QFORC method in the hysteresis of the Mn12Ac molecular magnet, which is governed by macroscopic quantum tunneling of magnetization. The QFORC reproduces well the experimental magnetization behavior. It is possible to separate the thermal activation and tunneling contributions from the magnetization variation, as well as associate the magnetization jumps with specific quantum transitions. (C) 2013 AIP Publishing LLC.1035Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Giant coercivity and high magnetic blocking temperatures for N2 3− radical-bridged dilanthanide complexes upon ligand dissociation

Single-molecule magnets typically only retain information in the presence of an applied magnetic field and at very low temperatures. Here, Demir, Long and co-workers design N2 3– radical-bridged dilanthanide complexes that exhibit giant coercivities and 100-s magnetic blocking temperatures of up to 20 K