1. Modulation of Jahn–Teller distortion and electromechanical response in a Mn3+ spin crossover complex
- Author
-
Grace G. Morgan, Plamen Stamenov, Fengyuan Zhang, Irina A. Kühne, Matthias Stein, Andrew T. Barker, Helge Müller-Bunz, Oisín O’Doherty, and Brian J. Rodriguez
- Subjects
Physics ,Spin states ,Condensed matter physics ,Band gap ,Jahn–Teller effect ,02 engineering and technology ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Spin crossover ,Local symmetry ,Lattice (order) ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,General Materials Science ,Isostructural ,010306 general physics ,0210 nano-technology - Abstract
Structural, magnetic and electromechanical changes resulting from spin crossover between the spin quintet and spin triplet forms of a mononuclear Mn3+ complex embedded in six lattices with different charge balancing counterions are reported. Isostructural ClO4- and BF4- salts (1) and (2) each have two unique Mn3+ sites which follow different thermal evolution pathways resulting in a crossover from the spin quintet form at room temperature to a 1:1 spin triplet:quintet ratio below 150 K. The PF6- (3) and NO3- (4) salts which each have one unique Mn3+ site show a complete conversion from spin quintet to spin triplet over the same temperature range. A complete two step spin crossover is observed in the CF3SO3- lattice (5) with a 1:1 ratio of spin quintet and spin triplet forms at intermediate temperature, while the BPh4- lattice (6) stabilizes the spin triplet form over most of the temperature range with gradual and incomplete spin state switching above 250 K. An electromechanical piezoresponse was detected in NO3- complex 4 despite crystallization in a centrosymmetric space group. The role of defomations associated with strain-induced spin triplet-spin quintet switching in breaking the local symmetry are discussed and computational analysis is used to estimate the energy gap between the two spin states.
- Published
- 2020