Alloying Effects on Intermolecular Magnetic Interactions in Verdazyl Radical Alloy Crystal, (TOV)_(1-x) (TOV-H)_x, x=0.0 approx 0.09 (TOV: 1,3,5-Triphenyl-6-Oxoverdazyl)

摘要

To study the alloying induced drasticantiferro/ferro change of intermolecular magnetic interaction in1,3,5-triphenyl-6-oxoverdazyl (TOV) radical alloy crystal,(TOV)_(1-x)(TOV-H)_x, measurements of high-fieldmagnetization, magnetic susceptibility, and powder X-raydiffraction pattern on this radical alloy have been carried out,where TOV-H is an amine precursor of TOV. Theantiferromagnetic (AFM) exchange interaction in pure TOVcrystal has changed drastically to ferromagnetic (FM) type byslight alloying (x=0.03), due to intermolecular distanceexpansion. The observed magnetization, M(x,H), for the TOVradical alloy at 1,7 K has shown deviation from a simpleBrillouin function, and thus the M(x,H) was analyzedapproximately by two terms. The composition rate dependence ofthe lattice parameters o15 percent between radicals along the c-axis at x=0.03. Based on the experimental facts, we will discussthe effects of elongation of inter-molecular distance on themechanism of magnetic interaction between the delocalized radical spins.