1H and 195Pt NMR Study of the Parallel Two-Chain Compound Per2[Pt(mnt)2]

Crystals

Elizabeth L. Green²  Lloyd L. Lumata³  James S. Brooks²  Phil Kuhns²  Arneil Reyes²  Stuart E. Brown¹ 

[1] Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA;Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA;UT Southwestern Medical Center, 5325 Harry Hines Blvd., NE 4.2, Dallas, TX 75390, USA;

关键词: organic conductor;    spin-peierls transition;    charge density wave;    nuclear magnetic resonance;    high magnetic fields;   

DOI  :  10.3390/cryst2031116

来源: mdpi

【 摘 要 】

¹H and ¹⁹⁵Pt NMR are used to probe the spin ½ anion chain in the quasi-one-dimensional conductor Per₂[Pt(mnt)₂], which exhibits nearly simultaneous charge density wave (CDW) and spin-Peierls (SP) transitions at low temperatures (T_c ~ 8 K). Below T_c the [Pt(mnt)₂] chain forms a spin-singlet state that is evident in ¹H NMR spectra and spin relaxation (1/T₁) rates; however minority unpaired Pt spins may remain in the SP ground state. With increasing magnetic field, the SP and CDW order parameters decrease in unison, indicating they are coupled up to a critical field B_c ~ 20 T. Above B_c, the spin singlet evolves into a spin-polarized configuration. The ¹⁹⁵Pt NMR signals vanish as either T_c or B_c are approached from within the SP ground state, suggesting the hyperfine field of the Pt nucleus is significantly stronger than at the proton sites. Simulations yield a consistent picture of the angular, temperature, and magnetic field-dependent spectral features.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.