Test of the Haldane Conjecture in a 1d-Heisenberg (S = 1) Antiferromagnet by Optical Linear Birefringence

Abstract

We report on optical linear birefringence measurements in the nearly ideal S = 1 Heisenberg antiferromagnetic chain compounds: Ni(C2HsN2)2 NO2 (C104) and Ni (CzHsNz)2 N02PF6. The temperature dependence of the magnetic contribution, proportional to that of the magnetic energy, indicates J / k = -53 K and supports the Haldane conjecture.Article published online by EDP Sciences and available at http://dx.

Update 1 of: Calorimetric Investigation of Phase Transitions Occurring in Molecule-Based Magnets

“…166−169 Magnetic heat capacities deduced from temperature dependence of optical linear birefringence were also reported on NENP and [Ni(en) 2 (NO 2 )]PF 6 (NENF). 170 These studies clearly showed that the magnetic long-range order is absent under zero magnetic field and that the spin gaps are dominated by the exchange interaction J along the chains rather than the single-ion anisotropy D of spin bearer Ni(II). The effect of external magnetic field was thoroughly examined to bring about quantum phase transitions.…”

Calorimetric Investigation of Phase Transitions Occurring in Molecule-Based Magnets

“…[166][167][168][169] Magnetic heat capacities deduced from temperature dependence of optical linear birefringence were also reported on NENP and [Ni(en) 2 (NO 2 )]PF 6 (NENF). 170 These studies clearly showed that the magnetic long-range order is absent under zero magnetic field and that the spin gaps are dominated by the exchange interaction J along the chains rather than the single-ion anisotropy D of spin bearer Ni(II). The effect of external magnetic field was thoroughly examined to bring about quantum phase transitions.…”

“…Among molecule-based Haldane systems, calorimetric studies were reported on a series of antiferromagnetic S = 1 Heisenberg chain systems, [Ni(en) 2 (NO 2 )]ClO 4 (NENP), NMe 4 [Ni(NO 2 ) 3 ] (TMNIN), , [Ni(dmpn) 2 N 3 ]ClO 4 (NDMAZ), and [Ni(dmpn) 2 N 3 ]PF 6 (NDMAP). − Magnetic heat capacities deduced from temperature dependence of optical linear birefringence were also reported on NENP and [Ni(en) 2 (NO 2 )]PF 6 (NENF) . These studies clearly showed that the magnetic long-range order is absent under zero magnetic field and that the spin gaps are dominated by the exchange interaction J along the chains rather than the single-ion anisotropy D of spin bearer Ni(II).…”