Proton NMR measurements of the local magnetic field in the paramagnetic metal and antiferromagnetic insulator phases of $λ$-(BETS)$_{2}$FeCl$_{4}$

Details Proton NMR measurements of the local magnetic field in the paramagnetic metal and antiferromagnetic insulator phases of $λ$-(BETS)$_{2}$FeCl$_{4}$ Proton NMR measurements of the local magnetic field in the paramagnetic metal and antiferromagnetic insulator phases of $λ$-(BETS)$_{2}$FeCl$_{4}$

2006-05-02

arxiv.org/abs/cond-mat/0605044v2

Physics

Condensed Matter

Strongly Correlated Electrons

11 pages, 7 figures. Revised version of cond-mat/0605044 resubmitted to Phys. Rev. B in response to comments of Editor and rev

Scientific paper

10.1103/PhysRevB.74.064428

Measurements of the $^{1}$H-NMR spectrum of a small ($\sim$ 4 $\mu$g) single crystal of the organic conductor $\lambda$-(BETS)$_{2}$FeCl$_{4}$ are reported with an applied magnetic field $\bf{B}$$_{0}$ = 9 T parallel to the a-axis in the $ac$-plane over a temperature $(T)$ range 2.0 $-$ 180 K. They provide the distribution of the static local magnetic field at the proton sites in the paramagnetic metal (PM) and antiferromagnetic insulator (AFI) phases, along with the changes that occur at the PM$-$AFI phase transition. The spectra have six main peaks that are significantly broadened and shifted at low $T$. The origin of these features is attributed to the large dipolar field from the 3d Fe$^{3+}$ ion moments (spin $S_{\rm{d}}$ = 5/2). Their amplitude and $T-$dependence are modeled using a modified Brillouin function that includes a mean field approximation for the total exchange interaction ($J_{0}$) between one Fe$^{3+}$ ion and its two nearest neighbors. A good fit is obtained using $J_{0}$ = $-$ 1.7 K. At temperatures below the PM$-$AFI transition temperature $T_{MI}$ = 3.5 K, an extra peak appears on the high frequency side of the spectrum and the details of the spectrum become smeared. Also, the rms linewidth and the frequency shift of the spectral distribution are discontinuous, consistent with the transition being first-order. These measurements verify that the dominant local magnetic field contribution is from the Fe$^{3+}$ ions and indicate that there is a significant change in the static local magnetic field distribution at the proton sites on traversing the PM to AFI phase transition.

Affiliated with

Also associated with

No associations

Rating

Proton NMR measurements of the local magnetic field in the paramagnetic metal and antiferromagnetic insulator phases of $λ$-(BETS)$_{2}$FeCl$_{4}$ does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Proton NMR measurements of the local magnetic field in the paramagnetic metal and antiferromagnetic insulator phases of $λ$-(BETS)$_{2}$FeCl$_{4}$, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Proton NMR measurements of the local magnetic field in the paramagnetic metal and antiferromagnetic insulator phases of $λ$-(BETS)$_{2}$FeCl$_{4}$ will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-184107